I have a 1994 Dakota with a 3.9L. It starts fine but after about two minutes of running it just starts loading up. I have replaced the Vacuum control motor and the coolant sensor and the problem is still there. It is noticeably worst the colder it is outside. The problem goes away when the motor temp is normal. This problem has been driving me nuts for a year now. Has anyone had the problem? Any help would be greatly appreciated.

 

Try replacing the t-stat. Maybe staying open to long.

 

I am assuming that the T-Stat would be the thermostat. How would it affect my problem? Thanks

 

It turned out that the O2 sensor was bad. Replaced it and the problem went a way.

 

3 years later?!?!?!