Guys,

96 Turbo H23. When I start the car... the rpm jumps up to about 2000 by itself, climbs to about 2500 slowly, then drops down to about 1500 and sits there... but once I start driving and go back into idle, it bounces up & down constantly unless I let off the gas pedal really really slowly. While the rpms jump up & down, my A/F gauge bounces up & down as well from rich to lean.

I have searched the topic, but nothing seems conclusive except a majority of postings saying maybe vacuum leak, but I don't think that's it.

Any ideas? This can't be from running too rich, can it?

 

Check you throttle body. Mine had junk in it from the previous owner. Or the valve, cant remember the name, right after the throttle body,

 

if you have a swap try checking the engine ground...throtle body positioning sensor...run some fuel injector cleaner. Try some of those things. Those are what I've found to be wrong on my friends cars.

 

It couldn't have anything to do w/ the throttle cable right? Like being loose or having too much slack, not tight enough?

I can't figure this one out and it's so embarassing to have your engine rev repeatedly on it's own at every idle.

 

how many check valves are you running....(open end t-fittings) you need a **** load on the H23 motor.... i have 6 i think...... next how's the pcv valve look.....replace it anyway... its 2 bucks... next check ALL and i do mean ALL the vac lines on the intake manifold one might of popped off which causes a high and wavering idle.....so does a bad pcv...the throttle cable has nothing to do with is..... you have a throttle return spring which keeps the throttle closed when not on the gas.... so thats fine.....unless that broke.....which i doubt, but hey doesn't hurt to check anyway.... i'd bet that the pcv is bad...... or a vac line is off.... or u need more t fittings on the vac lines to allow atmospheric pressure to eualize the system...... sounds all scientific n stuff, but not really..just pressure..... check it all out n let us know