Engine hesitation when cold


#1

My 98 Mitsubishi Carisma (similar to a Lancer) has a problem when engine cold, the engine seems to hesitate and sputter, and if I try to put it in gear it will only go very slowly. Once the engine is warmed up enough the problem goes away, any ideas whats causing this? Its an old car and I don’t want to spend a lot to repair it.


#2

One thing to check is a faulty coolant temperature sensor for the computer.

If the sensor is telling the computer that the engine is at operating temperature when it isn’t, the engine will run lean and won’t produce any power.

Tester


#3

I concur w/Tester that’s the first thing to do, as it is easy to test that sensor. The problem is that coolant temp sensors are not a common failure item. If the sensor tests ok, let us know. The engine requires special treatment when cold, b/c the O2 sensors haven’t warmed up enough to be working correctly, and cold engines need a much richer mixture to run well compared to warm engines, so if the sensor tests ok, there must be something wrong with all that.