Does anyone have any idea what might be wrong with my car? It surges up and down when idling. It doesn't alway do it though, its very random and it doesn't seem to matter if the car is warm or cold. I have replaced the IAC valve and cleaned out the throttle body and intake manifold. I have had it checked out by an Acura dealership as well as another mechanic and no one can figure it out. It started doing this about 3 days after I had a fuel induction service done at the local lube center. I suspect this somehow caused it but I have no way to prove it.

 

i would recommend two things
One maybe you TPS is shot or needs to be re-calibrated or
somethings wrong with you IACV
start with those two and if that doesnt work then will figure it out

-Brian

 

two of my friends had that problem and it was their air flow sensor

 

vacuum leak...is one of the ports on the intake manifold not capped? just a guess.

 

i had this problem and it turned out to be the valve inside the fast idle thermo valve (located underneath the TB) was just loose. all you have to do is tighten it up with a flathead screwdriver and your good to go. pull off your TB and pull off the little brass looking lid on the bottom of the FITV and the valve is right there.

 

I have the same similar problem, but if I lower the fuel pressure it goes away or if I lean or richen out the fuel mixture on the VAFC, it solve the problem.

Not sure if it is the right thing to do.

This only happens with the rechipped obd1 ecu, if I use the factory PCT civic type r ecu then there is no problem. Could the fuel mixture curve on the reprogrammed ecu be too much causing this fluctuation in idle????

Please help!!!