348 1-4 Intermittent Check Engine Light

happens all the time with 348. You need to figure out how to read the code first.

 

If your car has the original electrical connectors in the engine compartment, personally before doing anything else since the engine seems to be running fine, I would try to find every connector in the back and at least unplug and plug them back in a few times. Better yet, get a fine wire brush and try to clean all the little connector pins and see what that gets you. You don't want to go replacing $$$ parts based on a code that is just from a poor connection.

 

Read the codes. I would not be surprised if it's a lambda control issue due to a vacuum leak. A vacuum leak can effect mixture control at idle or low RPM and not have any effect at higher RPM.

 

Not too big a deal. The thermal coupler is heating up for some reason. Usually too much unburned fuel in the cat. Mine does this when I rev it up in second then let off the gas on a down hill section. Only after the engine has been running for a bit though.