Edmunds dealer partner, Bayway Leasing, is now offering transparent lease deals via these forums. Click here to see the latest vehicles!
Popular New Cars
Popular Used Sedans
Popular Used SUVs
Popular Used Pickup Trucks
Popular Used Hatchbacks
Popular Used Minivans
Popular Used Coupes
Popular Used Wagons
Comments
I am skeptical that your 98 Deville was any different than the 2004. Both cars have the same axle ratios and transmissions, so engine braking on hills should be very similar. However, the 2000 model year northstar was a new engine, and there may be some differences to the transmission too. However, GM's cruise controls have never downshifted to maintain cruising speeds. As I pointed out, on a steep hill downshifting into 3rd gear will improve engine braking. Below 40 MPH 2nd gear may be needed...
Recommendations:" This is normal engine noise and no repairs should be made in an attempt to improve it" END
In my case its more like two minutes after cold start, its not from the engine but sounds like a metal to metal series of taps in the lower rear driver side of the car. Will let you know if we run this to ground.
There is definitely something wrong with the programming of your vehicle (PCM, maybe?). I wouldn't deal with the service department much longer....I'd be on the phone with a Cadillac advisor pronto.
On level ground taking your foot off the gas should result in the car slowing down. However, if you are going downhill, you may well continue to accelerate or certainly not slow down much.
There is some possibility that the computer is adding some fuel to keep the engine running faster to compensate for the A/C compressor running, but perhaps the compressor is actually off. This would result in the car seeming speeding along with a mind of its own. Perhaps hitting the brakes kills this mode of operation. I would think that reprogramming the computer might fix the problem if there is a problem with the software, but if the original software is the problem, restoring it will do no good unless there has been an upgrade.
If your dealer has given up, then you should take the problem up with Cadillac. I think that your owners manual has information on how to do that.
I have never considered CU to be competent at testing cars or pocket calculators for that matter.
My previous two cars were reliable domestic vehicles which I owned for 5 years each. Consumer Reports didn't like or recommend either of them (Dodge Intrepid and Chrysler Concorde).
In our family, we currently have a 2001 Chevy Tahoe which has been absolutely bullet-proof since we bought it (CR doesn't like it), a '06 Cadillac DTS (CR doesn't like it either), and we just traded a very trouble-prone '99 Honda Civic for a new '06 Mercury Milan (the Civic had transmission problems, oil leaks, and repeat brake problems for the last 4 of it's 7 years with us....Consumer Reports loved it).
Are they biased? I don't know....but my experience is markedly different than theirs.
I have read their appliance recommendations, but they are somewhat behind the curve on improvements that the manufacturers make. They seem to rate things as average, above or below; and the differences between the above and below may be significant, probably the average products are as good or better than the products with the best ratings.
Mileage about 4100.
2006 Cadillac DTS III downhill inadvertent acceleration problem. The car is new.
I doubt if this is the same problem you are having, but it could be related. Our DTS does coast a lot when you kick off the cruise control at freeway speed. I haven’t noticed how much the rpms drop at that time.
This is a great car but it has some real quirks.
1. We live in hilly country. When going down hill the car will accelerate with your foot off the gas pedal about every 100 yards depending on the grade. This is especially bad on the turns. You do not expect a car to accelerate with your foot off the gas peddle on a turn or any other time. This is a safety issue. It takes excessive use of the brakes to keep the speed down and drive in a safe manor. When going down a grade we shift the car into a lower gear. The speed limit in town and the residential areas here is mostly 25 to 35 mph and in town the car should not even be in drive. The only time in town that it goes into drive is when you let off the gas peddle. This causes the car to coast excessively. We run the car mostly in 3rd gear around town.
The dealer has had the car for testing two times for several days. This engine revs up 600 to 700 rpms when this happens and you surge or speedup while going downhill with your foot on the brake. It is in the computer program to save gas, so the computer shuts off the gas when the car is pushing the engine for a short time. It slows down great until the surge. When the engine slows to about 1000 rpms, then comes the surge. When the gas comes back on to prevent the engine from dieing the rpms go up 600 to 700 rpms. The engine has a lot of power and you really notice the surge. The technician was able to reproduce the surging problem. This a built in computer function to save gas as explained to us by the dealer’s head technician. The technician said that the company has no repair for this car at this time. Unless there is a computer update, there is nothing to be done. If you are going down a grade you have to put on the brakes continuously to keep the speed down. This situation becomes dangerous while going around the windy down hill grades in hilly country like where we live. Right as we turn into our drive way this happens almost every time. It happens even with your foot on the brake. It is dangerous!
The cure for this is as I understand it from the technician and one of the owners at the dealer is to always drive in overdrive and use the brake instead of shifting down. This was their recommendation.
We have contacted Cadillac and they tell us there is no fix for this problem.
We contacted NTSB on May 1, 2006. They have not contacted us.
The acceleration problem is a safety issue the others are irritating.
Other quirks:
2. The max tire pressure is 30 on the door post, 44 lbs. on the tires. During the hot weather the pressure has gone up and the computer continuously flashes and makes noises. I lowered the pressure and it seems better.
3. The windshield wipers will run with the window completely dry, be sure not to leave the wipers on auto!
4. We are hearing a weird noise. It sounds as if it is coming from some part of the front of the car, also at around 70 mph. Other people are reporting is noise. There is no message being displayed. It is a buzzing sound and it comes and goes. I tried opening and closing the sun roof. This did not seem to make any difference. We will be contacting the dealer to see if they have any answers. I may have solved this one, I am not sure yet.
These problems take the fun out of driving this car!!
wps
Mileage about 4100.
2006 Cadillac DTS III downhill inadvertent acceleration problem. The car is new.
Has anyone had this problem?
This is a great car but it has some real quirks.
1. We live in hilly country. When going down hill the car will accelerate with your foot off the gas pedal about every 100 yards depending on the grade. This is especially bad on the turns. You do not expect a car to accelerate with your foot off the gas peddle on a turn or any other time. This is a safety issue. It takes excessive use of the brakes to keep the speed down and drive in a safe manor. When going down a grade we shift the car into a lower gear. The speed limit in town and the residential areas here is mostly 25 to 35 mph and in town the car should not even be in drive. The only time in town that it goes into drive is when you let off the gas peddle. This causes the car to coast excessively. We run the car mostly in 3rd gear around town.
The dealer has had the car for testing two times for several days. This engine revs up 600 to 700 rpms when this happens and you surge or speedup while going downhill with your foot on the brake. It is in the computer program to save gas, so the computer shuts off the gas when the car is pushing the engine for a short time. It slows down great until the surge. When the engine slows to about 1000 rpms, then comes the surge. When the gas comes back on to prevent the engine from dieing the rpms go up 600 to 700 rpms. The engine has a lot of power and you really notice the surge. The technician was able to reproduce the surging problem. This a built in computer function to save gas as explained to us by the dealer’s head technician. The technician said that the company has no repair for this car at this time. Unless there is a computer update, there is nothing to be done. If you are going down a grade you have to put on the brakes continuously to keep the speed down. This situation becomes dangerous while going around the windy down hill grades in hilly country like where we live. Right as we turn into our drive way this happens almost every time. It happens even with your foot on the brake. It is dangerous!
The cure for this is as I understand it from the technician and one of the owners at the dealer is to always drive in overdrive and use the brake instead of shifting down. This was their recommendation.
We have contacted Cadillac and they tell us there is no fix for this problem.
We contacted NTSB on May 1, 2006. They have not contacted us.
The acceleration problem is a safety issue the others are irritating.
Other quirks:
2. The max tire pressure is 30 on the door post, 44 lbs. on the tires. During the hot weather the pressure has gone up and the computer continuously flashes and makes noises. I lowered the pressure and it seems better.
3. The windshield wipers will run with the window completely dry, be sure not to leave the wipers on auto!
4. We are hearing a weird noise. It sounds as if it is coming from some part of the front of the car, also at around 70 mph. Other people are reporting is noise. There is no message being displayed. It is a buzzing sound and it comes and goes. I tried opening and closing the sun roof. This did not seem to make any difference. We will be contacting the dealer to see if they have any answers. I may have solved this one, I am not sure yet.
These problems take the fun out of driving this car!!
wps
The recommended minimum pressure is on the door post. The maximum inflation pressure designed for the tires is on the tires. The softest ride will come from using the door post pressure. A few extra pounds of pressure will not hurt anything, but the tire pressure monitor (I don't have one) may object to too much pressure. One should check the tire pressures on a regular basis.
As I pointed out above, when the torque converter is locked up, the engine is connected directly to the wheels and the RPMs will not drop when the cruise control is disengaged. However, I think that a second tap on the brakes should unlock the torque converter, but this is something to query the service manager about. This may be the whole problem in fact.
My Seville has a console mounted gear shift, which makes shifting much easier. I am looking forward to the tap up/down shifters that GM seems to be introducing with the six speed automatics.
Your axle ratio is 3.11:1 unless you have the high performance model. In 3rd gear your engine should run about 2000 RPMs at 50 MPH. What this means in terms of other gears is:
4th gear - 0.68:1 -> 1360 RPMs (torque converter locked - otherwise faster)
2nd gear - 1.63:1 -> 3260 RPMs
1st gear - 2.96:1 -> 5920 RPMs
I would have thought that any competent person would realize that a lower gear will speed up the engine.
5. When using the cruise control on a flat highway for example at 65 mph, when you hit the brake and stop the cruise control, the rpms drop only about 50 rpms. It does not matter how many times you hit the brake peddle to kick off the cruise. The throttle is not returning to idle when you kick off the cruise control. Even in 3rd gear the throttle does not seem to return to idle when you let your foot off the gas. The car takes forever to slow down. wpsr
As I explained in some detail, when your in gear the engine is connected to the wheels and if they are turning your engine will also have to turn. The torque converter will act as a fluid coupling or clutch and at speed will force the engine to spin. At low speeds the torque converter will begin to "slush" and will let the engine run at idle speeds.
If you check the instantanous MPG, you should see some difference between the MPGs when the cruise is engaged at 65 MPH, and after you touch the brake, disengaging the cruise, the instant MPGs should jump up to 70 MPG or so. If it does, then the fuel injectors have shut down. If the fuel consumption remains constant, then there is something wrong -> perhaps your throttle body is sticky?
My Crown Vic calls for 35 psi on the sticker, 44 psi max on the tire, I inflate it to 37-38 psi cold, slightly firmer ride, well within safe limits, and can leak out 2-3 psi and still be at 35 psi...:):):):):)
Regarding your bullet #2:
A tire pressure of 30 PSI is for normal loads and speeds. Maximum PSI of 38 (not the 44 on the tire side) is for higher speeds (100 MPH). This is all explained in the owner’s manual in the tire section on page 5-58. The page number is dependent on the manufacture date of the vehicle. Setting your tires at a cold pressure higher then recommended can set off the alarm warning as the tires warm up – I set mine at 32 PSI even though the label indicates 30 PSI and have not experienced any alarms yet. The higher pressure will also cause the vehicle to roll easier (less resistance) when you take your foot off the gas. This may be related to your bullet #1.
Regarding your bullet #3:
The rain sense wipers may come on as you described – see page 3-14 of the manual for an explanation.
Regarding your bullet #4:
If you only hear this noise when you accelerate – see my posting #308.
Good luck – hope this helps.
#4 - The noise only happens at 70 or 75, it sounds like plastic vibrating and I think that is what the problem is. There is plastic on either side of the hood latch. I glued it down and think it solved the problem. The dealer yesterday said they never heard of this problem. I see other people talking about it.
Thank you, wpsr
Your powertrain is not much different than mine, there is no reason for a surge.
I meant that if the carmaker sticker reco 30 psi cold, one could add 3-5 psi anytime and not be overinflated, that's all...if the maker manual says 38 psi for over 100 mph, then, by all means, do it, but I think it is a rare one who often exceeds 100 mph...then again, there is Texas and Montana...:):):):)
I don't know that it will make a difference, but try it and see if there is a difference by the end of the second tank.
I guess the TPM is esp good for telling you you have a slow or fast tire leak, acting as a warning for low psi rather than high psi, altho since we read about some repair shops putting 45-50 psi in tires, maybe having a top end warning isn't so bad...hey, maybe the "red flag" limit is adjustable, so I could set it at, say, 7-8 psi over where I keep them inflated...
We took the car in for service the other day. The master technician had not heard of the weird noise. I think I have fixed it. We have had the car up to around 75 several times since fixing the plastic. Raise the hood, there is a latch below on the vehicle. On both side of the latch there is plastic. This plastic is vibrating at higher speeds causing the sound. I used silicone sealer under the leading edge of this plastic to glue it down. If this plastic ever needs to be removed it should come off without too much of a problem. Apparently this plastic is not loose on all of these vehicles, not everyone is hearing this noise.
The noise in the trunk:
I have seen several complaints on another forum, these vehicles have a vacuum pump in the trunk. If the intake vacuum in the engine becomes low this pump will run to bring vacuum to a proper amount. If the pump is running excessively you could have a vacuum leak. It is common to hear this pump right after you start the engine and it is at idle, also if you stop with the transmission in gear and the engine running at idle. If this pump is loose it could be radiating the noise, it is a small vacuum pump.
Wps
Still no fix for the acceleration problem, see 2006 Cadillac DTS downhill inadvertent acceleration problem.
Thanks.
http://www.cadillacforums.com/forums/cadillac-dts-forum-2006-beyond/
http://www.cadillacforums.com/forums/open-letters-cadillac-corporate/
Go to the senior service rep at your dealer and have them loan you a car identical to yours. By identical I mean, in your case, a Luxury I, II, or III and also the same model year. I believe your post indicated that you have the 2006 Luxury III. The Performance version has a different engine and MAY not experience the same problem. I have the performance and have not noticed a surge yet.
Drive the same route that you do when you most notice the surge - like when you turn into your driveway.
1 – If the loaner displays the same surge then it may well be across the board.
2 – If the loaner does not surge then you have more fuel for the fire to fight GM.
In the second case it would be great if the service rep were with you.
Good luck. – fmoeller
That is a good idea, I have been thinking the same thing. Keep in mind, you must go down a grade that is steep enough for the car to push the engine. It is easiest to reproduce in 1st or 2nd gear. This is when the computer shuts off the gas. As soon as the engine gets to about 1000 rpms and the gas comes back on is when we get the surge of 600 to 700 rpms. The dealer's head technician here has reproduced the problem with our car and others on their lot, including a Buick with the same engine as the Cad. The problem is the dealer and Cadillac say this is normal, yes really hard to believe. We have contacted Cadillac direct and also NTSB. I think NTSB is on overload.
It will be a little while before I will have a chance to drive another car at the dealer. Thanks, wpsr