Idle problems

[Silent_sapper]

Hey guys I have been surfing the fourms for the past 5 hours and have been trying the suggestions that others have already posted ofr the idle relearn process i am hoping that someone can help me here. I have done everything that is states step by step it is doing everything as described but i cant get it to reset the RPM's. I get the car to running temp and the RPMs stay high and jump from 1500-2300 every few seconds. I have been replacing parts that "were" defective ie MAF sensor and now the throttle body because the idle controll sensor "was" bad. I dont know wtf to do anymore i checked for vaccuum leaks and cant find any. If anyone has any idea of how I can fix this please help me.

[03GXEDD]

Silent, you didn't list any car/engine info, so go here Index of /FSM/Sentra and click on the correct year Sentra. Download the EC pdf (engine control section) and do the procedure outlined on the bottom of page 52-55. I don't know if that is the procedure you have done before, but best to get the information straight from the shop manual. (Pages 52-55 are the pages you want from the 03 manual, maybe different pages in different years). Basically you're looking for the Accelerator Pedal Released Position Learning, Throttle Valve Closed Position Learning, and Idle Air Volume Learning procedures. If none of that works, check you throttle position sensor. The test procedure is on EC page 189 in the 03 Manual. Good luck, post back with the results.

[Silent_sapper]

Sorry thought I did was pretty tired at that point. It's a 2003 sentra se-r spec v pretty much stock. The main problem I am having is there is no CEL but based on the way the engines acting. I was told that it was prob the idle sensor going out since the Maf cehecked out. I did try the relearn it takes for a sec then when I rev it starts the erratic idle again

[boyrs]

are you sure you're letting the idle air relearn complete correctly? it might be a problem with ECU, and make sure you're not throwing code and your MIL just isn't working.

also check wiring and connectors where you can, i've been plagued with wiring problems on my 02 SER

does the problem ONLY happen when warmed up? if so it might have something to do with your ECU running in closed loop mode, which for my friend was a combination of problems with his spark plug gap, EGR valve, and a clogged cat. that made his truck idle high and slightly flutter his RPMs.

what happens when you start the idle relearn? how does the car act?

[Silent_sapper]

Im not 100% sure of what you mean with the idle relearn. I am following it step by step and the car is doing everything as it should. I then start the car after its completed flashing. All it does is go to correct idle for about 10-15 seconds then it starts reving up and down from like 1300-2000 RPM. It now is giving me a P0507 High RPM code. I have pulled pig tails and cleaned them with electra clean n such and hasnt done anything. My spark plugs are with in gap according to manual. I look into the other suggestions thanks.

I was also thinking before about clearing the cat i have done this on cars i have owned before would you reccomend this, or will that cause more problems with the car? Were i live i have no emission but currently i dont have the money to but a new exhaust or i would. but thats a totally diff subject. right now i just wanna get this idle under controll.

[boyrs]

the idle relearn was a pain in the @$$ for me... to do it correctly, i had to get a friend to time me while I did the relearn sequence... I figured out after the 20th time that I couldn't watch the clock and do it myself. my main problem was that i was pressing and releasing the pedal just a little too quickly (7a & 7b) when it says five times in 5 secs that's just what it means, not 5 times in 4.8 secs...

when I finally cranked it, the RPMs did go up and down, but it leveled back just under 750 and stayed. I could tell big difference between the relearn, and the way my car had been idling rough. if you're sure you are doing relearn correctly and it still isn't taking it, then there is something else wrong with the ISC system

the FSM says to check

Electric throttle control actuator

Intake air leak

PCV system


make sure you unplug battery when messing with the Electric throttle control actuator, if car is still charged, it will make you have to do the idle relearn all over again. if you disconnected this and then got code, it might be two different problems.

i would mess with the cat last, and it'd probably be better just to replace downpipe like you said when you get the scratch. but if you still have stock header w/ pre-cat, I would recommend replacing that as soon as possible.