Questions and Answers
LaSabre SES
Q. I have a 1991 Buick LaSabre. The car was running great with 247,000 kilometers on her, then, my problem began. The Service Engine Soon light would began coming on when I slowed for a stop sign and then disappear again upon acceleration. I took the car into the dealer who informed me that the oil pressure gauge was malfunctioning causing the SES light to come on and he even suggested taking the bulb out of the SES light, as his opinion was they were a waste of time.
I thought best to leave it as it was. Then the speedometer began dropping to '0' and the SES light would come on, even with NO speedometer, the car ran rough then the speedometer would kick back in and work properly, but the engine would miss terribly. If I stopped the vehicle and restarted it, the SES light would be out and the speedometer would work correctly and the car would again run great and then out of the blue the speedometer would again drop to '0' and the SES light would come back on and the car would run rough.
I have replaced the fuel filter, oxygen sensor, PCV sensor, air filter, and plugs. Does anyone out there know what else this could be. I really can't afford a lot of costly repairs.
Heather
A. I can't believe that you took your car to a Buick dealer and they told you the Service Engine Soon (SES) light was a waste of time. That light is there for a reason, to alert you to the fact that there is something wrong with your car. The fact that it comes on when the problem starts is a damn good indication that it works.
Heather, if I were you I would scratch that dealer off my list of places to do business with and go to a shop that knows a little bit more about what they are doing.
Basically It looks like the problem is with the Vehicle Speed Sensor. A good shop will be able to access the DTC the computer stored to confirm this. Even though the light is not on and the engine is running fine, the computer will retain the DTC until it is erased, either by a technician or a certain number of engine starts without the problem occurring again.
Additional Information provided courtesy of ALLDATA