1990 Buick Lesabre 1990 Buick Lesabre: Engine Misfirings/Su

JRSCOTT

MEMBER
1990 BUICK LESABRE
6 CYL
FWD
AUTOMATIC
106,000 MILES

I recently had some work done on the car which included replacing the head gaskets.

Since the head gaskets were replaced the engine seems to be misfiring a lot, with occasional surges.

The misfirings seem to occur as you get started and slow down. Once up to speed and staying nearly constant speed they don't occur as frequently.

What might cause this?

2 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Could be caused by the following:

Faulty spark plugs or wires
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector(s)
Burned exhaust valve
Faulty catalytic converter(s)
Stuck/blocked EGR valve / passages
Faulty camshaft position sensor
Defective computer
Possible SolutionsIf there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.

If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.E. Spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.K.A. Coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.