Question about 1991 Plymouth Colt
Just bought a 1991 Dodge Colt 1.5. type (A) (1468)Engine I.D. 4G15(A)
Only when the engine is cold,takes a few times to start,but it does start easy enough.It won't idle.I need to play with the gas pedal to keep it running,and it runs fairly rough while doing this.As the engine warms up,the car runs better and better. After 3-4 minutes,I can see that the engine temp gage shows fairly warm engine,and the idle is good on it's own.Engine smooths out and it runs very well.It will idle and drive and runs like it should.If I shut it off and restart it starts good,runs good only when engine is warm.I took it for a smog test,passed everything but the idle,to many hydro carbines.They said it's running to lean.So I replaced the O2 sensor,The Two wire coolant sensor,looked at whatever vacuum hoses I could see.Changed the fuel filter and spark plugs,changed oil and filter.It only runs bad when engine is cold.Once warm it runs good???????Any help at all would be great.Thanks.Mike.
Im having the same issue also with a 4g15, but a Mirage. The first poster is overlooking that the issue happends only during cold starts up entell the engine is at running temp. It could be the EGR cylanoid, wich funnels hot exhaust air back into the intake in order to heat and regulate emissions. In my case my car has been over heated in the past and has a cracked head gasket wich is leaking water from the rateator into the cylenders, on idle I find a small ammount of water coming out of the tail pipe, once the engine heats up it turns to smoke, then goes away ( built up water in the cylenders from it sitting for a substancial period of time ) check on a cold start to make sure your not getting any smoking out the tail pipe, could also explain the ruff idle entell warm up. IAC ( Idle air controle motor ) regulats idle mainly when things like AC/heater is on btw.
Posted on Oct 21, 2009
Most likely you have a bad Idle motor which is a small motor mounted on the intake manifold. If the motor can run better with your foot on the gas but dies if removed then it is probably this. This motor is controlled by the OBDII computer which gets it's control signal from the temp sensor which is located either on the radiator or engine block (which could also be bad), if the electric fan (if equipped) turns on then this is not the problem part, but the idle motor is. Another possibility is that you have some bad /cracked vacuum hoses which should be checked for first, before replacing the idle motor.
Posted on Nov 30, 2008
probably oil, it may be too thick when it's cold but once it warms up it liquefies and your engine runs smoothly. you could try changing oil, I'm guessing if you have a high performance oil the chances this is the problem may be greater since high performance things are usually geared towards working well when everything is hot
Posted on Jun 29, 2008
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