At idle my car has always seemed to rev up and down without any throttle appled. When it's cold it idles normal but then when at speed after about 10 minutes driving when it's warmed up and you coast to a stop it starts surging up and down. it thought it may be the ECM so I changed it out, but then the one I just got from Poston gave a check engine light and never went off and idled terribly erratic, even worse. Took it out put the original back in and the check engine light went off, but the weird idleing is still present. It's always done this a little since I got the car new in 89, but it seems to have progressed to pretty bad as of today. Any thoughts on what this is?
Cam sensor? Bad ECM? I have a Scanmaster, what would reveal itself through the scanner if anything at all?
Cam sensor? Bad ECM? I have a Scanmaster, what would reveal itself through the scanner if anything at all?
