Questions and Answers

Ford Thunderbird Runs Rough Damp Q. 1990 Ford Thunderbird. In damp weather it runs rough and has the tendencies to stall. Please help us out. Thanks, Terry

A. Nine times out of ten when an engine does this in wet or damp weather, it is due to a secondary ignition problem. Distributor cap, distributor rotor or ignition wires.

What you can do to confirm this is to start the engine and let it run. Then, with a spray bottle, spray the distributor cap, distributor rotor and ignition wires with water. If the engine starts to stumble and break up, then you know the problem is in the secondary ignition system.

You will also hear and see the ignition spark jumping around. If you do this in the late evening when it is starting to get dark, the jumping spark will be easier to see.