Hello peeps,
Car has been resting for a few months but it's about time to bring it back. Before it's back on the road, I had this odd RPM fluctuation problem which I wasn't able to debug. The engine is a fully built Boosted B18c1.
Basically if you turn on the car, the car idles fine no problems what so ever for it sits at 1k(its set on the ecu to idle at 1k). With the car in neutral, and you press the gas to say hold the RPM at 2k/3k or any RPM the RPM would go up and down. I know this does this if the IAC/FITV is bad at idle but while the RPM is up and trying to hold it steady? t
The fluctuation is around 500rpm for it goes up and down pretty steady and you can feel it slightly when driving in gear.
Thinks checked/tested:
Injector seals, checked and changed
Intake manifold for cracks - crack free(mani is new)
Changed Manifold gasket twice
EACV/IAC/FITV - checked, swap for testing and same
ESS - plug was changed (old one was corroded but sensor is good)
compression is 185-190psi on all 4
nothing is registering on the S300 for there are no errors what so ever
The TPS and MAP are 2 items that I had not tried but before I continue to troubleshoot in the wrong direction it is best to ask for help.