I’ve asked this before but couldnt get a straight answer:
Alright when I turn on my car it shoots to about 3k, then it will drop to 1k then back up to 2.2k and it will keep going from 1k-2.2k… When I let it roll by its self in gear it will raise to 2k then drop like someone slammed on the brakes to 1k and then raise again to 2k. and it will do this over and over… When I hold the gas lightly it will jerk like crazy. If I take the TPS off it will run fine except the idle will be at 3.5. If i try to adjust the idle screw nothing happens. If i take the IAC it think that thing behind the manfifold off it will have a very lopey idle like a V8 sounds cool but not driveable. any ideas? This happened after I put a 91 manifold + PnP head on. I have a 92 LS.
did you check the pcv valve and hoses and with a vacuum gauge even. when the pcv valve has a leak the rpms go up and down like you said, dont know about the other symptoms
Who did the porting on the head?? Hopefully it was done right and they didnt mess up the flow characteristics of the head…
Try pulling the IACV and spraying it out with some brake cleaner, WD40 or something that will clean it out then spray it with air to get all the fluid out. You will need a compressor or some compressed air to do this part. Slap it back on and see if that helped.
I have managed to fix a couple idle problems with that trick.
Originally posted by XDEep did you check the pcv valve and hoses and with a vacuum gauge even. when the pcv valve has a leak the rpms go up and down like you said, dont know about the other symptoms
I’m a newbie to fixing my own vehicle so bare with me. What is the PCV? Pressure control valve? Where is it located. I’m looking through one of the online manuals and under the cooling system but could not find anything related to PCV. I have a similar idle problem in my 90 Teg GS. I’ve noticed that my upper radiator hose is swelled up and needs replacing but I’m not sure if this has anything to do with my rough idle. I’ve searched the forums and couldn’t find an answer that I can understand so here I am. Thanks in advance.
I’m a newbie to fixing my own vehicle so bare with me. What is the PCV? Pressure control valve? Where is it located. I’m looking through one of the online manuals and under the cooling system but could not find anything related to PCV. I have a similar idle problem in my 90 Teg GS. I’ve noticed that my upper radiator hose is swelled up and needs replacing but I’m not sure if this has anything to do with my rough idle. I’ve searched the forums and couldn’t find an answer that I can understand so here I am. Thanks in advance. [/B]
pcv is positive crankcase ventilation. its in the exhaust or emissions section i forget. its behind the fuel rail in the middle of the intake manifold, and the hose goes up to the right side of the upper part of the manifold. mind you when it leaks the surging is large and obvious, so if you just have a slight surging its probably something else.
ya you should definitely change the hose. its very easy, just drain the coolant, replace and refill. just remember to loosen the bleed bolt. all can be found in the haynes or helms manual.