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Mitsubishi Diamante



  • abesabes Posts: 2
    The sunroof in my 92D LS is experiencing some problems. I have to use both buttons ( slide and tilt) to open the sunroof and close it. It also has gotten stuck on me a couple of times. It did not tilt before, now its does but then it doesnt close. I am going to try to fix this problem myself. I know this is not a major problem since I can manually close the roof, but i was just wondering if anyone has had a similar problem and if there are ony suggestions to the cause and the fixing of this problem. Thank you


    P.S. I would like to
    thank Mr. Vivona for
    refering me to his
    article on cleaning
    your throttle body,
    very helpful, thanks
  • taurus2taurus2 Posts: 63
    Is Mitsubishi going to stop making Diamantes? I read that in Automobile Magazine something about the last "waning," days of the Diamante.
  • We are looking at a used 1993 Diamante with 80,000 miles on it for $7995. We are wondering about any mechanical problems and the longevity of this model. Are there any questions other than the usual (accident, usage)that we should be asking? Is this a decent price or should we be negotiating down? The exterior and interior are in excellent shape with no rust, rips or stains.
  • I recently purchased a 1998 Diamante LS and when the air conditioner is on, the car is very "jerky". It feels like I am pressing and releasing the gas pedal constantly. In previous cars that I have owned I have felt changes in the power occasionally when the air is on, but not nearly as constant as this. Has anyone else had this problem and if so, is it something that can be fixed?
  • lngtonge18lngtonge18 Posts: 2,228
    Is the model you are looking at an ES? If it is, I owned one of those with very high mileage and can say that for the most part it is a very reliable car. I bought it with around 160K and sold it with 173K. I just talked with the current owner at a gas station and she now has 183K with no problems. Things to look for is any smoke coming from the exhaust. The SOHC V-6 is known for valve guides that wear prematurely and burn some oil. Mine was well-cared for so it only burned about 1/4 of a quart every 3K which is normal for something with such high mileage. But cars that weren't so well cared for can burn a quart every 1K, which can get annoying. Check to make sure the tranny shifts into first gear smoothly when stopping at a moderate pace. Mine would slam shift into first with an obnoxiously loud bang and jolt. Manually turning off overdrive with the switch before stopping circumvented that problem. I also had a problem with the engine not wanting to idle with the AC on. Cleaning the throttle body fixed that problem. If you feel any hesitation when accelerating, the most likely cause is a cracked distributor cap or bad plug wires. The distributor cap on these cars only last about 1 year due to its close proximity to high heat. I also had the famous warped rotor problem. These cars tend to warp their rotors rather easily so check to make sure there is no vibration in the steering when braking hard. Overall though, the car ran great. It has good power, so-so fuel economy (expect 18-20 mpg in the city and 25 max on the highway), never left me stranded, always started first time, felt extremely solid even after all those miles, and the interior held up very well. As for the price, I think I would try to get them down to $7K. The Diamante has poor resale value and the fact its 9 years old should be reflected in its price. I bought a 97.5 Altima with 60K for $7500. I know that its not a luxury class car, but its reliable, quite a bit newer, has most of the same power equipment, and has lower mileage. So keep that in mind when negotiating on such an old car. Good luck on your search and I hope I have been of some help!
  • vivonavivona Posts: 410
    taurus2--As I interpret the line in Automobile Magazine, these are the "last waning days" of the current model run. The current model started in 1997 and is expected to run until 2004 or 2005, so Mitsubishi has done a mid model run "freshening" on the front and rear of the car. If the link is still there on this page, (upper left under Additional Resources) click it to see the video and hightlights of the 2002 Diamante.
  • taurus2taurus2 Posts: 63
    Thanks a lot! I heard that the Mazda Millenia will be gone in 2003. I was just wondering with that line "last waning days," if the Diamante was goin to be retired soon. With all the new Technology in mid level luxury cars today it would be smart to remodel the Diamante in 2003 to keep in race with Lexus, Infiniti, Acura.
  • Hello,

    I'm Jack and I have 1995 Diamante LS with DOHC engine, currently my car has 81,000 miles.
    I have experienced with the same problem as Michelle "mkc" has. I'm taking my car to the dealer tomorrow for the repair. I hope that it will not break my budget and dealer will not rip me off on the invoice.

    Michelle would you send me email with answer what was the problem with your dying Diamante?
    My email is
    Thanks a lot in advance!

    Streamwood, IL

    P.S. I'm happy that I have found this forum!
  • vivonavivona Posts: 410
    What most Americans do not realize is that the Diamante in Japan and Australia does have a lot of the same modern technology as its competitors, including in-dash navagation, auto-stick transmission and gasoline direct injection (GDI). Since the Diamante is not sold through a separate dealer network like Toyota does with Lexus, Nissan does with Infiniti and Honda does with Acura, Mitsubishi has to keep the price point attractive and that means leaving out some of the more pricey stuff. Also, with the limited production capacity of the Australia plant, only about 10,000 Diamantes are available for us (US) so it isn't economical to have options that may only be bought by 10-20% of the buyers. On the other hand, I do hear that the 2002 Diamante will have a VR-X model added which will have a sport suspension and more horsepower along with some sporty styling.

    Mr. Vivona
  • mkcmkc Posts: 20

    Will e-mail you as well. Mine turned out to be the idle control motor had shorted out - "old age and mileage", they said.

    With oil change (needed anyway) it came to $607.


  • slk321slk321 Posts: 1
    I took my 2000 Diamante with 22,000 miles to the dealer to have a fog light replaced and to tell me why so much road noise.

    They told me the road noise is caused by the tread on the tires on the outside being worn - I beleive they used the words cupped.

    When I asked how this might happen the dealer said tire pressure or alignment. They offered to sell me new tires but this seems like a waste since the Goodyear GA have a lot of tread life left.

    Why should I do?
  • Michelle,

    I got your email. Thank You very much for your quick response. You really helped me out, coz I know what should I check to fix the problem I'm having right now with my Diamante.

    I see your problem went away but it cost you $600 to get it done. Ouch!

    Thanks again Michelle!

  • mkcmkc Posts: 20

    Since your e-mail to me mentioned that your D would still idle, I would suspect it might not be an idle control motor. In my case, once the engine had warmed up, the car would die unless I kept my foot on the accelerator. When it was cold, there was no evidence of a problem.

    Also, a drop in idle under load (from 1000 in neutral to 650-800 in drive) might indicate something like a vacuum leak, air/fuel mixture, spark, etc. some of which are controlled by the ECM using readings from the sensors. I think the MAP sensor is one specifically which adjusts air/fuel/spark based on engine load.

    If you search the Web on Mitsubishi Trouble Codes, you should come across the instructions for using a voltmeter to probe the Data Link Connector near the fuse box (I found it at ). It also tells how to read the 12V pulses and then what these codes mean. Long pulses occur first, which represent the "10's" place, followed by short pulses, which are "1's". Then it repeats.

    So if you get 1 long pulse followed by 3 short pulses, this translates to trouble code 13 and the lookup chart says this is Intake Air Temp Sensor Fault.

    Multiple codes (they start with the lowest number and go up, so for example I got a 13, 25, 31) probably mean something else has failed.

    Typically, the Check Engine Light comes on if there's a true sensor fault (but not always).

    You mentioned your D is a '95 with 80-something K. How recently have you had the EFI system serviced (plugs, wires, fuel filter, fuel-injector cleaning)?

    As a data point, my D now idles in park with no load around 650 rpm and in drive or park with A/C on at around 1000 rpm. Idle is steady with no significant fluctuations (although the park-idle seems a little low and I keep forgetting to check the under-hood sticker to see what spec is (it's an ES, which should be SOHC, I believe).

    Mr. Vivona - any wisdom you can share on Jack's symptoms I'm sure would benefit all as well.

  • Looking for others that have experienced this particular problem when applying the brakes.

    I have had this problem at 6,000 miles, 11,000 miles, and now again at 21,000 miles.

    Would like to know if there are any fixes out there that work, for longer than 10K miles. Also, does anyone know any contacts at Mitsubishi to call about this. I have called dealers and customer relations only to get told 'no problems'.

    Thanks in advance.
  • timtrantimtran Posts: 29
    Mitsubishi had tried different rotors on the Diamante (pre 5/99, 5-6/99, and post 6/99)but had no remedy to warped rotors. Exert care when installing them, or when changing tires (see Diamonds and pearls by Mr. Vivona) may help new aftermarket rotors last longer.
    Instead of going back and forth with Mitsubishi about this issue, I proactively replaced my original rotors (which indeed got warped) with Beck/Arnley rotors that can be ordered at NAPA auto parts or Kragen for less than $200.00 a pair, tax included. Installing them is a snap, it took me 30 minutes for both.
    If you follow Mr. Vivona's directions, they should not give you any problems in the future. Stay away from manufacturer's rotors, my Mitsubishi service advisor told me so. IMO $200.00 is a small price to pay for peace of mind, and the unnecessary aggravation for dealing with the manufacturer. Hope this will help.
  • dtownfbdtownfb Posts: 2,918
    I don't have a Diamante but have had "cupped" tires on my 96 Explorer. There isn't much you can do except replace them. I was told it''s a product of not rotating the tires. It only happpens on the front tires of my Explorer with about 34,000 miles. Replaced them about 40,000 miles.
  • ccancioccancio Posts: 91
    I'm getting prepared now to replace all my disc brake pads and have started buying all the gear I need to do the job.

    I've read some reviews and now have opted to try out the EBC "Green Stuff" brake pads (US$79) for the front. They unfortunately do not have pads for the rear so I will probably go for MetalMaster for the rear ($49).

    Now I'm toying with the idea of replacing the rotors as well with some "vented" ones eventhough my current rotors are working perfectly fine ( you have to understand my to spend the money somehow rather than just spend it on something silly like food and housing ;-) )

    What I want to know is what are the actual steps to replace the rotors. I've read the "poor" Chiltons manual and it looks *too* simple to be true!

    Any "gotcha's" to watch out for, eg. like make sure you have so and so part before proceeding???

  • Hello,

    It's me again! I recently had a problem with my Diamante. It was the same problem as Michelle had with her Diamante. The problem was in idle speed control motor. When the engine had warmed up, the car would die unless I kept the foot on the gas. There was no problem when it the engine was cold.

    Therefore, looking at the Michelle's "mkc" post on this forum, I purchased this part and have it replaced by my mechanic. Everything took only 10 minutes and now my car runs OK! I can even say that engine has more power and I can't feel upshifting or downshifting of the transmission that occured before replacing the ISC motor.

    My bill was for $450.00
    Towing $125 + parts & labor $325.00

    Thanks a lot Michelle! Once again you don't know how much you helped me with my car's problem :o)

    Streamwood, IL
    1995 Diamante LS (DOHC)
  • mkcmkc Posts: 20

    Glad to hear I saved you $150 over what my repair cost ;-)

    I guess I'd misread the e-mail you sent directly to me as well - I thought in your e-mail you were reporting a low/rough idle problem, not the actual warm engine stalling one.

    Out of curiousity, let us know how your gas mileage is over the next several tanks. I'm not sure how much timing/idle speed setting was done by my dealer when they replaced my ISC motor, but I went from a typical 22.5-23.5 mpg (for the past 6 years) to 24.5 on the second tank of gas after the repair and 25.5 on the 3rd tank since. This is the highest fuel economy I've ever gotten in this car, and it has 125K miles on it.

  • timtrantimtran Posts: 29
    It was indeed a "no brainer" job: check this site out: for details. I believe it was a 17mm socket/wrench instead. It sounds like you are using a combination of organic pads (short life span)in the front, and metallic pads (wear rotors)in the rear. The original pads are semi-metallic. I would stick with semi-metallic ones.
  • Could someone please tell me where the idle speed control motor is on my 94 Diamante? I'm having the same problems as described by other posters and am going to go ahead and buy the part and replace it myself. I was just wondering if any of you know where exactly it is on the engine. I have the ES SOHC engine. Please be specific. Thanks in advance.
  • lngtonge18lngtonge18 Posts: 2,228
    Just curious: Have you cleaned the throttle body yet? My 93 D ES SOHC developed a stalling problem that would only occur when the engine was hot. At every light I had to keep my foot on the gas to keep it running. There was no warning to this stalling, it just suddenly started occurring one day. Turns out the throttle body was all carboned up and had clogged the 2 small air bypass holes (they bypass the throttle butterfly valve which is closed at idle) that help the engine idle. All i needed was a $2 can of throttle body cleaner, a small soft cotton towel, and a rod of some kind that can help push the towel around in the deep recesses of the throttle body. You just spray the cleaner into the throttle body (you take the air intake tubing off to get at it) and use the towel to wipe out the build-up. Very simple and very cheap. It solved my stalling problem, twice in 1 year! Apparently, the throttle body gets gunked up pretty easily. The towel was practically black the first time I did it. I would try doing that before you go spending money on an expensive part that may or may not fix the problem. And just to warn you, the car will run rough for the first few minutes after spraying the cleaner. Just let it burn off and it should run smooth again. Hope this saves you some money!!
  • bob_pabob_pa Posts: 18
    Well I've had my Diamante for 7 months and a little over 4000 miles.

    Overall I would rate this the best car I have ever owned so far. I love the comfort, power, and style.

    Regrets: Black paint! I will never by black again. Silver next time, or blue.

    Problems: I had all 4 of my tires replaced by good year for excessive run-out and really bad vibration. The new tires were then balanced at the dealership. Its a lot better but Im getting ready to take it back for this again.

    I also had a rattle in my dash that the dealer fixed.

    I love this car. I just want my vibration fixed! I am going to see if they will put a different brand tire on.
  • I love my black 99 Diamante, but I'm having a hard time keeping it looking good. Normally, I wouldn't buy a black car, but this one was new, and about $3,000 below INVOICE!

    I have had it for nearly two years and 24,000 miles, and have had only two minor problems with it, that were easily fixed by the dealer.

    However, I'm starting to have a few problems with my brakes (which have been well documented here), so timtran's advice in the earlier post has been printed out -- we just need to find a good Japanese import shop that can install them.

  • Ingtonge - Unfortunately my problem is not a dirty throttle body. As suggested by Vivona's article, I disconnected the air hose and checked for grunge. There was a little, but not much at all. So, I'm due for a new idle speed control motor. Again, if any of you know where this is on the engine, please let me know, so that I can figure out what I'll need to do to replace it. Thanks.
  • lngtonge18lngtonge18 Posts: 2,228
    Mine didn't look dirty either to the eye. What matters is whether the holes are clogged. You cannot see whether the holes are clogged from just peering into the throttle body. But cleaning it sure fixed my stalling problem. You should give it a try, whats the harm? Even a little grunge will cause the problem. Seeing as I had to clean the throttle body twice in one year to alleviate the problem, it apparently occurs often. I would try the cheap and easy fix first before spending money on something that may not fix it. But it may in fact be that idle speed control motor. If it isn't, you saved $150 and a few hours of your time. If it is, it cost you $2 more and 10 extra minutes. At any rate, good luck to you.
  • Thanks for the advice. I'll clean it really well this time. If it doesn't work, however, I'm still interested in where the idle speed control motor is on the engine. What size is it? What exactly does it do? Is it a motor, or just a relay? Thanks.
  • vivonavivona Posts: 410
    I was reading through Carpoint and noticed that they have updated the reliability information for the Diamante. All years get the top rating!

    The only problem area noted with the 92-95 is moderate problems with the timing belt on the DOHC engine and occasional failure of the Idle Speed Control motor. The 92-94 also shows a moderate problem with air conditioning but that is only because up to 94, Diamantes (like most cars) have R-12 Freon and all cars with R-12 Freon get that rating because repairs are expensive due to the cost and scarcity of R-12.

    The 96-99 has no problem areas at all.

    It is interesting to note that no year of Diamante shows a problem with brakes. This supports the research I did for my Diamonds and Pearls article on brake pulsation which said that the brake problem in a minor occurence that is created by overtightening of lug nuts or improper shop practice during brake repairs.

    To check out the Diamante reliability ratings, visit

    Mr. Vivona

  • vivonavivona Posts: 410
    Get a copy of the Chiltons Galant/Mirage/Diamante 1990-00 Repair Manual for $18 from

    On page 4-9 there is a diagram and instructions on how to check and replace the motor. It is called the Idle Air Control motor in Chiltons, but it is the same thing as the Idle Speed Control. It is mounted on the throttle body and turns the throttle shaft. The repair procedure in Chiltons is simplified and will get you going. To set up a new Idle Speed Control motor takes the procedure listed in the official Mitsubishi Diamante Service Manual for your year of Diamante. You can order that manual from Magauto (see below), but expect it to cost over $100.

    If you need the part, check the price with who sells at wholesale to the public.

    Mr. Vivona

  • I am looking at a Diamante LS with all the options including chrome wheels. I had the following questions about the car:

    1. What does the remote entry do? I have only seen a galant remote and it only locks an unlocks the doors. Other cars have a panic button and trunk opener and was wondering if the diamante's remote does this?

    2. What does the engine require/prefer in term of fuel octane?

    3. One of the options listed on edmunds was a luxury group. How do I tell if the car has this?

    I also wanted opinions and what to look out for? I like these cars because they are sleepers in the market and sell for less than competing models. Thanks
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