1989 Buick Century Missing UNder Load and Stalls In Gear

Question: I have a 1989 Buick Century 112,000 miles with a 3.3L V6. I have put new plugs, O2 sensor,wires, ignition module, fuel filter, 5 fuel injectors serviced at NAPA and bought a new one. The car runs pretty good when first started, as the engine warms up it misses under load and then misses at a idle sometimes stalls when in gear. Should I check for a clogged catalytic converter or ??”

I doubt if it’s a clogged converter, because they have definite symptoms such as the engine will begin to run hotter on the temperature gauge, and the car will not be able to go over a certain speed (a small clog may limit you to fifty, a big one can limit you to ten miles per hour top speed.) First, I would really question the injector repair. If one injector was replaced, and the others merely cleaned, you may never get it to run correctly. The new injector is going to flow differently than the other old five ones, and odds are those five are on their way out like the one you just had replaced. I would start there to begin with. Also have the fuel pressure and volume tested, as a weak fuel pump can give your symptoms. And of course, replace the fuel filter as that’s simple and cheap. Good Luck,