Mitsubishi Repair: Cold starts, fuel pressure regulator, spocket


Question
I own a '99 Lancer, 1.5, GLi Manual.
This problem has been going for quite a while. After car has been parked for a while (approx 6 or more hours), either day or o/night i have to depress the accel pedal a little to keep the revs up to stop it from virtually shuddering to a stall, if i move straight away the car can be extremly sluggish. Also before car has warmed up if i depress the clutch for a few seconds while driving the engine will just cut out (even when travelling at speed ie. 70kph). When warmed up it is fine. My last mechanics attempted remedy was a bottle of injector cleaner and an idle timing adjustment. What do you suggest my next mechanic look at.

Answer
James,
This could be a problem with your Idle Air Control (IAC) motor.  It's job is to regulate the amount of air that bypasses the throttle plate when the car is idle.  Typically when the engine is cold, it bypasses the most amount of air and is not supposed to start functioning until the engine warms up.  If the IAC is not functioning properly, it may attempt to adjust air flow when the engine is cold, and that can cause your stalling and stumbling.

Though you may simply need a tune-up.  That can include, but not limited to replacing the following :
- Air filter
- Fuel filter
- Spark plugs
- Spark plug wires
- PCV valve

The fuel pump, fuel pressure regulator, and timing belt should be checked.  If your mechanic was able to adjust the idle timing, he should be to verify your timing is correct, and has not slipped any teeth on the cam spocket.  If the timing belt has appeared to have slipped, it would be a good idea to replace your timing belt and tensioner.
Good luck!