RPM jumps on deceleration

jthaut
Sun, 18 Oct 2009 16:12:55 +0000
Maintenance/Repairs

While cruising at any given speed, I will come to a stop sign or red light or a situation that causes me to take my foot off the gas. The idle will stay at whatever the cruising idle was for about 2 seconds, then increase a couple hundred RPMs, then come down to the normal RPM. The car actually accelerates a tiny bit with my foot off the gas. Even with my foot on the brake when coming to a stop sign, the idle goes up a tiny bit with my foot on the brake.

List of parts I’ve thrown at this 2002 SL1 with 86k miles for 1 year now:

plugs and wires twice over 2 years

fuel filter

cleaned carbon off egr and throttle body

pcv valve, helped out a lot, but still trouble

thermostat

idle air control valve

throttle position sensor

What is telling the car to get gas when I take my foot off the accelerator? Thanks for any suggestions.

27 posts - 11 participants