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Slipping/Non-responsive Throttle in 2007 Sienna



  • Just a little under heavy acceleration. Kind of a deep tone. Under normal use I can not hear any difference. I can sure sure feel the difference. Was worth the money for sure. If driving to conserve fuel you are supposed to gain MPG by a few. We shall see. I usually get 18/25 with 90% city here in PR. Plus the A/C is ALWAYS in use. But of course with a lead foot adding an intake will decrease your MPG.
  • caravan2caravan2 Posts: 198
    What is this? Please explain how this work? What improvement you have seen by this device?
  • All you are doing is freeing up the engine to breath easier. The easiest way to do this is replace your stock pierce of junk Fram or who ever air filter with a k&n lifetime air filter that flows air much much better. Plus you never throw them away, just clean them with one of their cleaning kits every 15,000 miles or so and your good to go.

    Replacing the whole intake does the same thing plus 20% more.. When it comes to power. But understand one thing more HP means more fuel so an intake can work in both ways. Baby the engine you will get better MPG. Stomp on it and you will have more power but worse MPG then before. Personally I think they are well worth the money.

    You can always do the same thing for your exhaust system and you will not loose any MPG. Such as high flow cats, larger exhaust pipes, high flow muffler, dual exhaust, headers. Though I doubt they make them for mini-vans.

    Full intake could get you 15+ HP, probably at least 10 on a good exhaust setup. 25 horse power is a good gain believe me. Hope this helps, let ne know if you have any other questions.
  • caravan2caravan2 Posts: 198
    I was at Autozone yesterday and they had K&N flyer. He was claiming that you'll get 4-5 Gallon savings on each fill-up. I don't buy that..... that is way too much!

    Have you seen any improvement in the mileage? I think HP is fairly good on Siennas.

    2nd Q: Does this voids your warranty?

    How much does this cost? Is it DIY yourself job?

    FYI... K&N does not make filters for SIenna :mad: Maybe someone else made it.
  • caravan2caravan2 Posts: 198
    Is this K & N filter?
  • First off adding an intake does not void any warranty. If the intake failed and a piece of it came off and got sucked into the engine and they could prove this then this would void a warranty.

    Second: Babying an engine with an intake should get you 1-2 MPG. How many gallons that is at the end of a tank you will have to calculate. Go to their site and check them out and yes they do make filters for the Sienna.

    I would suggest for your needs just get a replacement filter not a whole intake.

    Third: It has only been half a tank of gas since I added my intake and right now I am noticing between 1-2 MPG increase.

    This is what your filter will look like.

  • caravan2caravan2 Posts: 198

    This filter is expensive $54. I don't know how much regular Sienna filter would cast.

    I seem to recall that someone in the forum said it costs $40 at your local auto shop for intake replacement?
  • Well, consider you will never have to buy another air filter again. Also, look around you should be able to find it for upwards of 35 - 40 bucks. On the K&N site it will list dealers in your area and you can call them for quotes.

    Understand I am in Puerto Rico so prices here can be wacky. The K&N cone filter at pep boys here was 79 bucks. I was not going to pay over 80 with taxes for a filter. They had a another filter there, cone style, that was even bigger and rated just as good as K&N that I purchased for a little over 40 bucks. It was called Power Adder. I had never heard of them before but these type of filters, performance that is, are really all the same. I made the intake myself for my Sedona since no one makes an intake. I did not replace my intake tubing I just removed my airbox and retrofitted the air filter to the end in the stock intake tubing right after the MAF. (mass airflow sensor)

    I know sounds a little scary but it took me like 15 min to do and is working great. By the way what year and make is your van?
  • caravan2caravan2 Posts: 198

    You're correct that they claim that it lasts longer BUT they say, it has to be cleaned with oil that is sold by them. I'm not sure how much that oil costs.. but is not cheap, I'm sure...

    Mine is 2007 Sienna.

    Is your OEM filter is also cone?
  • The cleaning process is really easy, just spray the cleaner on the filter and let soak for a bit. Use a hose and you hose the filter from the INSIDE OUT!! Not opposite! Let dry for an 1/2 hour in the sun and spray the oil on the filter and let dry for a bit and your good to go. Take hour and half to do with dry time in the sun. Don't dry the filter any other way cause it could cause the material to shrink. K&N is just superior technology for airflow and cleaning then cheapo filters. Cleaning kit was under $10 bucks when I purchased it.

    No mine came with a cheapo fram type air filter and my original K&N filter looked just like yours. Flat and about the same size. The cone was an addition of my own since it is more flowing you just have to retrofit it on your intake tube or get a full intake.
  • rivkagrivkag Posts: 1
    How about the 2008? I have this problem- took it back to the dealer twice, and they say the same-- no big deal- the computer is trying to decide which gear, etc etc.

    Also said- no one is complaining about it.... :mad:

    To me, it feels like my old chevy van did before the transmission failed.

    What's a girl to do?

    Please keep me posted!

  • ateixeiraateixeira Posts: 72,587
    Go ahead and complain to NHTSA, click here:

    If enough people complain that they find a pattern, they can force Toyota to fix it.
  • Hi there - I've experience the exact same issue with my 2008 Toyota Sienna. The hesitation in shifting at low speeds when accellerating after slowing down to turn a corner occurs intermittently but is quite noticeable. According to those in the know, this issue is absolutely linked to the "drive by wire' system, or as the service manager likes to say "it's a characteristic of the vehicle" . My mechanic friend Jamie put it best when I was expalining the issue to him the fact that Toyota Canada was unable - or unwilling - to find a fix for the problem - he said " I've got a solution - it's called a throttle cable". Nicely put.
  • ateixeiraateixeira Posts: 72,587
    My theory is just a tad different:

    wwest was saying something about the trans waiting for revs for pressure to build up in order to shift, and there being a longer-than-usual delay when it has to downshift two gears (i.e. 4th to 2nd after a right angle turn).
  • wwestwwest Posts: 10,706
    "..linked to the "drive by wire".."

    Well, sorta.

    Due to a transaxle design change beginning back in '98 your transaxle is NOT able to complete, QUICKLY complete, a downshift that immediately follows an upshift.

    DBW has many positive aspects but in the instance is used as a "cover-up" for the design flaw. In instances when the downshift cannot be quickly completed DBW is used to delay the onset of rising engine torque even though you have re-applied pressure to the gas pedal.
  • wwestwwest Posts: 10,706
    Your ABS pumpmotor assembly includes a pressurized accumulator, holding a few ounces of pressurized brake fluid in "reserve". When ABS activates then this reserve pressure is used, INSTANTLY used, to replenish the pressurized brake fluid just previously "bled" off by the anti-lock system. The resulting sudden reduction in reserve pressure triggers the "on" cycling of the ABS pumpmotor to reactively replenish the accumulator fluid pressure.

    Prior to ~'98 Toyota (all marques..??) automatic transaxles had this same "feature". ATF line pressure was always sustained at a fairly high level using the ATF gear type pump, a fixed relief valve (3000PSI..??) and an accumulator to provide a reserve source of ATF line pressure in situations, brief situations, wherein the ATF pump could not replenish (engine idling) the fluid pressure as fast as it was being "used".

    Like your "old" hydraulic power stearing pump the parasitic losses of this technique are a substantial detriment to FE. The PS pressure pump must be sized to provide full functionality even in the worse case. For the power stearing pump this happens to be with the engine idling during parking, say parallel parking. Now, drive straight down the road at 70 MPH and just imagine the volume of hydraulic fluid be pumped only to be bypassed directly back into the sump having reached ~3000PSI.

    Same for yesterday's ATF gear pump.

    The pressure relief spring/valve has been replaced by a solenoid PWM control system such that the ATF line pressure is now under constant, "real-time", control by the engine/transaxle ECU. "On demand" ATF line pressure, no accumulator needed, nor desired.

    So the ATF line pressure can be dropped to some minimum level, maybe even ZERO, when conditions warrant. No detriment to FE when driving along, cruising, constant speed cruising, at 70MPH....2200 RPM. No un-necessary level of ATF pump loading as you climb, accelerate, through the gears, engine ROARING to 5,000 RPM at WOT.


    Require a quick downshift immediately after an upshift, an upshift having resulted from a lift throttle, FULL lift throttle event.....Engine RPM has dropped to idle and there is NO reserve ATF line pressure.

    (***1) '99 or early '00 F/awd RX300..expect transaxle failure within 50,000 miles.

    (***2) Late '00 F/awd out for BURNED ATF.

    (***3) '01 and later F/awd RX300..burned and dirty ATF in as little as 40,000 miles. Either drain/flush ATF each 15,000 miles or check ATF condition at each engine oil/filter change.

    (***4) RX330...DBW adopted to delay rising engine torque until transaxle shifting can be fully completed. Driver's begin complaining of HAZARDOUS situations when acceleration is unexpectedly, inadvertently, delayed for 1-2 seconds.

    (***5) RX350...Firmware revised, driver now being "watched".
  • ateixeiraateixeira Posts: 72,587
    Require a quick downshift immediately after an upshift, an upshift having resulted from a lift throttle, FULL lift throttle event.....Engine RPM has dropped to idle and there is NO reserve ATF line pressure.

    Like in my speed bump scenario.

    You let off the gas to slow down for a speed bump, then hit the gas after going over it, and you sense that hesitation.
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