[428CJ]

Once my pos, 1988 Mustang GT, gets warmed up, I've noticed that whenever I engage the clutch to shift the rpms raise 500, and then lower after a couple seconds. It also wants to idle at 1300 rpms once it warms up, rather than the 800 when its cold. Also, I changed the oil with 10w30 synthetic and now the car ticks after 2300 rpms. Anyone have any suggestions to fix my pos' problems.

Just replaced:

ECT, ACT, IAC
cap, rotor, wires,
and the O2 sensors

[94FiveOVurt]

I have the same issues on my 94 5.0

I cleaned my IAC, Throttle Body, MAF, IAT. RPM will also hang at around 2K with clutch in or out until I completely come to a stop then it will come down to about 1k.

From the research i've done, its either a vacuum leak or TPS needs reset to spec via Base Idle Reset procedure.

[428CJ]

Ya, when i let off it stays at the same rpm for like 5 seconds then lowers.

[79fox]

could your throttle be sticking?

[428CJ]

Originally Posted by 79fox could your throttle be sticking?

I doubt that my throttle is sticking because it works perfectly fine when the car is cold. The issues only occur once the car is warmed up.

[PsyAbe]

Eliminate all vacuum leak possibilities by checking the vacuum lines and all things related. Here's a diagram to help you out, make sure you've unplugged MAF or equivalent to let the engine run on default values before spraying.

[95tbirdv8]

sounds like a vacuum leak to me too. i had the same problem and i couldnt figure it out. one day for some reason i reached behind the intake and the vacuum line was unplugged from the pcv valve.