Losing Power

My car is losing power; spits, sputters and runs rough after the engine warms up. Waz up? 1987 LeBaron - 4 cyl., automatic, non-turbo.

When was the last time that the spark plugs were replaced?
How about the air filter, fuel filter, and spark plug wires?

If you don’t know when these things were last done, or if it has been more than 20k miles, then you need to replace all of those items.

I checked the air filter, it looks good … replaced only 3 months ago. The engine was replaced just 4000 miles ago including plugs, wires and distributor parts. Shortly after replacing the engine I drove 2400 miles to relocate from Michigan to Washington state. On the way to Washington I experienced the same problem; it turned out to be burned contacts inside the distributer cap. My mechanic in Michigan failed to plug the wires firmly in place causing arching and the damage was done. Since then I have driven only about 300 miles. I have not yet changed oil from the trip but it looks good on the dip stick. I have replaced the fuel filter (inline) before traveling to Washington state. I will check the fuel filter, air filter and distributer cap again. Could this be an O2 sensor?

Just change the fuel filter. Then check the fuel pressure. Also have the exhaust system checked for obstructions.

Did you replace that distributor cap and rotor, again? Yes, again–since you say it had arcing.