Thread: Bouncing Idle... all on its own...

Hi all, I've had this problem for a while and have replaced multiple sensors etc to try and fix the problem to no avail...

I have an '03 Spec, with Nismo cat-less headers, performance downpipe (no-name stainless steel), full Nismo cat-back exhaust, and Cold-air-intake. When I did the headers, I added a spacer for the 'post cat' o2 sensor (because it is high flow. Also both sensors are located on the header). I have replaced both o2 sensors, throttle body/tps sensor, all 4 ignition coils & spark plugs, crankshaft sensor, camshaft sensor, and have cleaned all parts possible without decommissioning the engine.

Also I'm reading no codes (ses light off). I just tried a full ecu reset/ pedal release position relearn/throttle position closed learn/Idle air volume learn as posted by Sash (idling rpms 1500-2000 - B15U.com - Nissan Sentra Forum) Thanks for that btw Sash. However, it did not help my problem.

The only 2 things I have not replaced yet that I think could be causing/contributing to the problem are the MAF sensor and the ECU... for cost reasons I don't want to replace these if they are not needing to be replaced.

If anyone has any ideas please share.
Thanks all!

vacuum lines?

Yeah it sounds like you might have a vacuum leak. It might be worth cleaning your MAF sensor too.

MAF sensors in our cars are junk, try cleaning it. if that doesnt work buy a new one.
Could always check for vacuum leaks first to be sure. just spray soapy water on the lines and look for bubbles. if you see any, thats your leak.

Does anyone have a vaccum line chart? I've looked at all lines I can guess to be vac lines, but want to make sure... or just if anyone knows how many tubes (#) I need to check...

bump, same f-ing problem this morning. bouncing from 1500-2000

I had the same problem, it was the intake manifold.

I hope that's not the problem... I still haven't been able to get out to check vacuum lines, it snowed 3 weeks ago and has been raining since then... no garage = can't feel fingers...

damn, so i did all the relearn stuff and the idle is no longer bouncing. It is still sitting high at a 1000-1100rpm and SES is on. will see what codes its throwing and take it from there.

i had the same thing happen to me mine fluctuated between 1000rpm to 1700rpm...i shut my car of for exactly 1 min and started it and it was gone...but i threw a fresh SES code for P0507 - Idle speed control system. any one else get this kick in the nuts?