engine chugs and stumbles upon acceleration.
I have replaced egr valve, air filter and sprayed throttle body cleaner into running engine. all these measures seemed to solve the problem for awhile. Symptoms reappeared immediately after putting in6 gallons of fuel yesterday. I'm replacing fuel filter in a few minutes. I'm wondering if there might be a more likely cause for this frustrating problem in an otherwise good running 5.7L motor. Any suggestions would be appreciated.
a fresh coil pack would be nice,even if its not the problem
When was the last tune up? You might try a good injector cleaner in the fuel, this stuff they call fuel anymore is terrible.
Where did you get the gasoline?
Could be a problem with the EVAP system. The EVAP system routes gasoline fumes back to the engine to be burned instead of being released into the air. If your purge valve is stuck open raw gas or excessive fumes may be getting forced into the engine when you get gas. This will cause an overly rich air/fuel mixture which will make your engine run poorly. Especially right after you buy gasoline. Since your Buick is a 1992 model it is OBD I & will not set a trouble code for this. It MAY set a trouble code for a rich oxygen sensor. Is your "service engine soon" light on? HTH. -Jim
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