Poor gas mileage in 2001 Grand Prix
 

Getting louzy gas mileage on Pontiac 2001 Grand Prix

Alright??? Are you looking for help as to diagnose why? we need more info to be of any help at all
HAs it happend all of the sudden
or was is gradual?
any SES lights? stuff like that

Threads Merged due to being same thng in two deiffrent sections!

Spoke with danthurs on 3/25, got a tune up but no luck. Spoke of PCM

so where do I go now??

What exactly did you and Dan discuss....What was done in your tune up? I.E. What parts were replaced???

Had a mechanic look at the car, said plugs were fine @ 92,000 miles. Checked O2 sensor said it was clean. Checked PCM said it was not bad. Dan mentioned that the PCM should be recalabrated.

Getting 10 miles per gallon in winter

winter blend fuels do no good for mpg anyways but wouldnt kill it that bad..Were the spark plugs and or air filter replaced? pcv valve how is tire pressure...Was the catalytic convertor checked?

I then talked to a GM dealer. He said tha if the PCM is bad a light woulld go on on the dashboard.Could this PCM be adjusted?