97 pont bonneville ssei - 100,000 miles

I had purchased this car about 6 months ago and the car was doing about 25mpg. All of a sudden the fuel gauge had started going funny so I had replaced the sending unit and fuel pump(fixed that problem). The car has droped milage dramatically to a whoping 12mpg after doing that(over a period of 2 months). I have had the car looked at by a shop and they had found an relay for the supercharger that was bad but nothing else......I was hoping that the relay was going to take care of the problem......anyway anyone here have any suggestions or run into this before? Please let me know as I would hate to get rid of the car.

btw I do have access to alldata but was not able to find anything there pertaing to the dramatic fuel milage loss other than the basic checks(plugs, wires, ect...).

Thnx

I got better gas miles on my 94 Bonneville after changing the Ignition wires, Platinum plugs and O2 sensor, you can try that.

I got better gas miles on my 94 Bonneville after changing the Ignition wires, Platinum plugs and O2 sensor, you can try that.

Thnx

what kinda milage where you getting and how much did it change?

I didn't mention on my original post but I did check the fuel regulator also for leakage..

Since you have a supercharge vin code 1 engine you also have a 2 stage fuel pump. Did you replace the pump with the right one called for your engine or did you use an aftermarket pump that possibly could be the wrong one?

Since you have a supercharge vin code 1 engine you also have a 2 stage fuel pump. Did you replace the pump with the right one called for your engine or did you use an aftermarket pump that possibly could be the wrong one?


I did replace the fuel pump with an aftermarket one from NAPA....they were specific on the engine code as far as being the supercharged...How would the fuel pump cause the fuel milage to keep decreasing?

Thanks for the responce.