1990 3.3 rough running until wamed up

[wrenchead90]

does anyone have any idea what would cause my 3.3 to run rough until it warms up.it backfires and acts like it wants to die.i have changed the coils,coolant temperature sensor,map sensor,tps sensor,and have checked fuel pump pressure,replaced fuel filter.i have also changed plugs and wires,but it still runs rough.any help would be greatly appreciated.

[yale329]

Hey freind, let me know if you find a solution.

[fubufolks]

I had the exact same problem with a Pontiac Phoenix until my neighbor (a mechanic) told me what was wrong. It was the automatic choke pull- off. It took me $50 and 5 minutes to fix it myself. Good luck.

[bridget36907]

does a caravan have a choke pull?

[fubufolks]

It's actually called a choke pull-off. I believe every vehicle with an automatic choke must have an automatic choke pull-off. Best way is to call a discount auto parts store and ask them, "How much for an automatic choke pull-off for my vehicle?" If there isn't one, they'll tell you.

[tazman]

While replacing the choke pull-off you may want to clean the throttle body. Disconnect the large hose coming from your air filter chamber and spray a throttle body cleaning solution into it. Follow the instructions listed on the side of the can or bottle before starting.

[RABarrett]

All of these people are referring to the days when a vehicle had a carburetor. In fuel injection, all fuel delivery is controlled electronically, not with user replaceable parts. I would try scanning the vehicle for codes. My suspicion is that either the vehicle is not warming up fast enough, or some sensor is confusing the computer into thinking the same thing. If no codes are set, it will be necessary to check each sensor for correct readings. It sounds to me like the mixture is too rich up until the time that the computer reads the O2 sensor (closed loop.) The O2 sensor, when it reads a rich mixture will tell the computer so and will lean it out accordingly. Until the engine warms up enough, the computer is basing the fuel delivery on air flow, coolant temp, throttle position sensor readings and a software package. If one of these is off, the result will be incorrect fuel delivery. I have not examined the vehicle; I am guessing, but this is an educated guess. Ray

[dodgerunner]

Check to see if you have an idle air motor. If it is dirty and sticking might be your problem.