'90 Celica GTS rough idle?

[SeanNQ]

Hey there,

So I just recently bough a Celica GTS off an old friend, and the test drive went smoothly. Bought of course, as soon as I got it home, things started going bad.

Sitting in the driveway for a moment, I started to feel the car shake when the engine was idling. I ran the engine up to 1.5K RPMS and it smoothed out, but you could still feel it, just barely. As soon as you let it drop down to the 1K, its horrible again.

Temperatures were fine, no trouble codes. I've Isolated it to the 2nd cylinder from the right, and I've already checked plugs/wires and done compression tests on all 4 cylinders. Fuel injectors are also working fine.

So, does anyone have an idea as to what could be causing the engine to run rough?

Thanks in advance.

[RobMilkshakes]

The 5SFE is notorious for having a bad idle due to the Idle Air Control Valve. Pick up some Seafoam deep creep (some recommend any throttle body cleaner, but not all are safe for plastic coated parts, and the seafoam seems to work well), remove the air intake hose from the throttle body, just inside before the butterfly, there is a hole in the bottom of the throttle body, this passageway leads to the idle air control valve, spray some cleaner down in that hole, repeat a few times, and while you're at it clean the butterfly and rest of the throttle body. Let it dry completely, then reassemble everything. This seems to work for most owners.