View Full Version : Rough Idle Needs TLC

03-14-2014, 02:00 PM
Car: Celica 1990 GTS.

Rough idle (especially with warm weather; not bad in cold weather), hesitation sometimes while accelerating or driving.

What I've Done to Address this:
Changed: Spark Plugs, Distributor Cap, Rotor, Fuel Filter, Thermostat, O2 Sensor, Cleaned K&N Air Filter, Cleaned Intake Air Control Valve, Cleaned Throttle Body, Used Fuel Injector Cleanor, Used Premium Gas.

Code shown is 26 which is mixture is rich. When the engine is running there's a "hissing" sound near the air cleaner, though can't find any leaks in hoses. Also, the Intake Air Sensor is a dark colour, should.

Any assessments on the rough idle based on what you've read? Would really appreciate any direction. TY

03-17-2014, 09:02 PM
1990 and a rich mixture that's a problem in warm weather makes me wonder if the cold-start timing switch is no longer cutting off the cold start fuel injector when the engine is warm. These earlier 5SFEs have a separate fuel injector for cold starts to richen the mix, which is supposed to cut off based on engine temp.