Mechanics

RUNS ROUGH AT IDLE

1999 Toyota 4Runner

Engine Mechanical problem
1999 Toyota 4Runner 6 cyl Two Wheel Drive Automatic 168000 miles

Bought the car a year ago and it ran fine for 6 months. Then it started to run rough while sitting at the stoplight---only sometimes. Eventually it started to cut off when idle, again only occasionally. Replaced plugs, wires, all 3 coil packs, mass airflow sensor, fuel filter, cleaned throttle body, fuel injector cleaner (in tank and in manifold) etc. No check engine light comes on unless it shuts all the way off. The only code I got was a misfire in #5 cylinder. No codes since replacing the coil packs. The car runs great otherwise, but once you stop at the light, or wait in the school pick-up line, it cycles. It will run great at 700rpm, and after a min or two will slowly go down to 600, 500, and nearly choke at 400rpms. Once it chokes, or almost chokes, it will cycle right back up to 700-800 rpms and sit just fine for 2 or 3 minutes. Then it slows back down again.
Avatar
Ross007
May 13, 2010.




Clean out the idle air control and test the throttle position sensor and mass aiflow meter

Tiny
Rasmataz
May 13, 2010.


AD