RPM goes up to 1.5k when pressing the clutch while slowing down
 

anybody experience while driving and when you're about to stop and press on the clutch, the RPM goes up to 1,500 (sometimes even up to 2,000) for 2-3 seconds then goes down gradually?

this only started to happen after i had my fluids changed (engine oil, tranny and diff fluids) and installed a Cusco clutch line and replaced my filter element. TB was also cleaned in the process and clutch fluid was replaced and bled in.

had the shop who changed my fluids and installed the clutch line and filter and a friend mechanic check my car for loose hoses which might cause the idle issue but found nothing. im just waiting for my tuner to get back so he can check on the car as well but that would be 4 days from now.

car has the GReddy v1 kit and Ecutek if those information would help?

to add, idle is around 1k when aircon is off which is a little high. anybody knows what causes these RPM issues? i plan to put back my old (and very dirty) filter and clutch line just to try to see where it went wrong.

You have added a pile of variables to the tune and intake so pretty hard to figure out what it could be. I think having the tuner take a look is probably your best bet. Anything else is just guesswork and could be way off base.

@Tcoat, you're right but maybe somebody had this experience already and can share since 4 days is quite long and been having this issue for 2 days already. tried to disconnect the battery and let the ECU relearn but that didnt work out

if anybody has any idea or guess while i wait for my tuner to get back, that will be appreciated so i would know where to look at and maybe fix the issue

OK, I'll play .......guess what is causing the erratic idle ..... :)

I'd start by checking to make sure the filter is properly installed and check the MAF connections and the all the intake box connections and hoses.

There ya go ...... ;)

Back-in-the-day, I would suggest you check the fast idle thing-a-ma-job, to make sure it was staying off the fast idle notch after the engine was warmed up ........oh, humfrz - go take a morning nap ...... :rolleyes:

Just didn't want you to go on a wild goose chase. If it was stock we could make some pretty good speculative guesses but with all you have done things get muddy fast.
No CEL or codes thrown?

I'm going to guess that it's throttle body related as I just replaced my throttle body with the Grams throttle body and am having literally the same issue and haven't figured it out yet. My car is also turbocharged on Ecutek. I've just been dealing with it for the last several days and haven't had time to take a look. The throttle body swap was the only change that was made to my setup. My issue could be related to the increased flow entering the manifold, but it's unlikely that yours is the same unless your throttle body was insanely dirty.

I'm not sure that it's related to your dirty air filter as that is pre-MAF. The increased airflow through the clean filter should be detected by the MAF sensor and the car should behave correctly.

I'd also say and go with rechecking the throttle body and check the MAF sensor. Car is normal to idle around 900 when tuned.

appreciate the replies, guys.. looks like i just have to wait for my tuner to get back so he can do a datalog since no CEL can be diagnosed from scanning the car

Ever get this resolved??

Update for anyone who has a similar issue:

My car has been tuned with OFT for 2 years now and I just recently cleaned the mass air flow sensor and throttle body for the first time at 71k miles. The car idled high right after first start up and would idle at 2k RPM when slowing down when back into a parking space and using a little throttle. I figured it was just the ECU relearning the idle, so I gave it two weeks to settle. Two weeks came and went with barely any change.

After doing some research and ending up here I made my previous post to see if anyone had any ideas, they didn't. A friend suggested I reflash my tune to stock the put the tune back on. So I gave it a shot and it FIXED the funky idle, now the car pull smoothly and idle normally.





TL;DR: Car with a tune idles high and funky after cleaning MAF and TB, reflashed the tune and problem goes away.

thank you so much tCsonfrs and your friend, too!

i have OFH UEL Stage 2 91..over the weekend i installed oem oil cooler and coolant bypass, did oil/filter change, tranny/rear diff drain/fill, bled brake/clutch, cleaned air filter and throttle body.

after i found this thread, i flashed my stock tune then back to stage 2 91 and that weird engine revving problem went away.

Reving an old thread but this is exactly what has happened to my car after cleaning the throttle body. I’ve already flashed the stock rom and flashed back and it’s still doing it.

Did you let the car idle and run on the stock tune?

Fixed the issue today by buying a used throttle body.

When I cleaned my throttle body I had taken off the molybdenum coating off the throttle body walls and butterfly. The molybdenum is there to libricate and seal the valve. So if anyone ever decides to clean their throttle body I would recommend you remove it and clean it properly with coating safe cleaners. Don’t use a towel to rub off the grey looking stuff on the throttle body!

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