I recently replaced the fuel pump on my 1991 firebird 305 tbi ,and i have noticed a significant drop in fuel milage. I used to get about 265 or more miles every full tank. now im getting about 220 mile every tank, but i've also noticed that my idal is a bit higher around 700 to 800 in park. and when i drive at about 45 to 50 mph the tach is at about 1300 to 1400 now im not to sure if that is normal running lines or not.. im not very good with the tech on car's yet Any suggestions? thanks

 

Maybe you tweaked the fuel level sensor arm.

 

so you saying i should still be getting around 260 miles to a tank just go by the trip gadge

 

did you disconnect your battery when you replaced the pump?

 

Yes I took the ground cable off the battery before I started

 

yu may have reset your adaptive fuel trims... I'd keep track to see if the mileage goes back up.

 

Sorry this might be a noob.. comment but what would that be and should it fix itself

 

computer controlled vehicles constantly monitor the amount of fuel being delivered. the vehicle will adapt itself to driving habits. when the battery is disconnected you may have lost the information the computer had stored. continue driving the car... the adaptives will "re-learn" according to how you drive and how the engine runs. short answer yes it should correct itself. if not you may have other issues.. I'd give it a few tanks of gas before you go crazy.

 

Cool thanks man I will give it a few tanks and see I hope this is only the first tank I have ran through the car after the change I just know the car pretty well and at 1/4 tank I'm usually at almost 240 miles or so the last 1/4 drops pretty quickly and I'm under a 1/4 now and just now rolling over to 200 so I'm pretty sure its not gonna make the 265 Mark this time