Questions and Answers

Dakota Runs Rough

Q. My question is I have 1990 Dodge Dakota pickup, automatic, A/C, P/S, P/B. It was running fine. I was driving on the highway about 65 to 70 mph. when I finally came to a stop it was running rough idling bad. It seems to run fine at higher rpm's, but runs very bad at lower rpm's or from a stop. I need to know steps to take to discover the problem. I have checked the spark plugs and they appear to be fine. It almost seems like electronic fuel injection (carburetor looking injection unit on manifold) is pumping to much fuel.

Thank you for your help.

A. You have throttle body injection on that engine. Kinda like a glorified carburetor. They are always injecting fuel so it may just look like it's shooting too much. The spray pattern should be circular with a fine looking mist. No big drops or dribbles. If there are, then you need an injector cleaning or new injectors.

There are a few possibilities for this condition. If there is black smoke coming from the tail pipe when the engine is running rough, then that's a good sign that it is running rich. Possibly a bad O2 sensor telling the computer the car is running lean. The Mass Air Flow (MAF) sensor, engine coolant temp sensor and Throttle Position Sensor could also cause this condition.

Another thing to look at is the spark plugs and wires. Pull a couple of plugs and look at them, if they are worn out, you will get that rough idle as well. I would also look around for a vacuum leak. That is another distinct possibility.