93 j30t idle occassionaly fluctuates from 1100rpm-2000rpm

08-17-2009, 05:28 PM
on my 93 j30 my idle occassionaly fluctuates from 1100rpm-2000rpm at idle.not under load.most of the time it idles normal at 800-1000.When this problem happens it would raise and lower about every15-20 seconds.i have no MILs or codes.i cleaned out the maf sensor and i could not detect any vacuum leaks.could this be caused by a faulty TPS,bad O2 sensor,bad injector,clogged pcv etc...i know it could be a bad iacv but im hoping thats not the case ($750).is there a way to test and/or clean iacv.Any info would be highly appreciated. thanx

09-14-2009, 08:33 AM
There is a vacuum line on the J30 that runs directly to the IACV. I will get some pics tonight. There is a way to do a quick fabrication to allow you to clean it while the car runs. This sounds like the most probable issue. Have you checked the PCV on the side of the plenum? I know the hoses are a pain to work with so it wont be easy. If you are into upgrading some hoses, I'd recommend getting the silicone PCV and IACV hoses from Z1 for the NA 300zx. They will always be easy to work with and wont rot out.

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