1990 Oldsmobile Cutlass fuel economy

KAM1959

MEMBER
1990 OLDSMOBILE CUTLASS
6 CYL
FWD
AUTOMATIC
14,400 MILES

The car at one time was only getting about 8 mpg after a repair. They replaced a broken spark plug wire with a complete new set and also one of the coils. The fuel economy quickly degraded to about 8 mpg. So I replaced the plugs and they were slightly fouled out. I put in new splitfire plugs and the mileage doubled to about 16 mpg. It should be about 20 or more am I right? My thoughts are a weak spark. The car lacks power and does not miss or hesitate. Could the ignition control module or the other coils be bad? Could the EGR valve be the problem if it is dirty or clogged? What about the charcoal canister? Someone also mentioned the timing. Do you time a car without a distributor?

1 Reply

LEGITIMATE007

MECHANIC
5,121 POSTS

Yes you can time a car without a distributor but it is only through the cam shaft and crank. Lining up the two at top dead center. I think you need to look into your o2 sensor. And find out if it is at all faulty. It will cause alot of problems with gas mileage and will cause the engine to run lean or rich making the plugs foul out. How is your heat? Is your engine ligh on?
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