i have a 1996 pontiac Sunfire and im haveing a fuel mileage...

[Bizquit]

...problem!!!!!!!!!!!!? im personaly get 18 miles to a galon. i did a tune up, ran fuel injector clener, inflated tires, oil change, shift at 2500rpm each gear what else could be the problem? *also have a sputtering sproblem when starting if anyone could help with that*

 

[john m]

First of all, their is no injector cleaner that does the job you need done after the fact. You have build up and need the injectors cleaned and the sputtering will go away.

See Doctor Injector on the web site and if your in a area where you can get to a shop that has this equipment use it, it is the best thing short of a replacement of new injectors.

also doctor injector has a product for keeping your injectors clean, now that can be done!

I have been their and got the shirt and the simi and a 04 Cumm, and a few big cam's under my belt I had to rework because of dirty injectors, so I learned the hard way to keep then clean first, and not have this cost later.
Good luck,
John

 

[wde3477]

Suggest to check the computer for any codes, some of which may result in poor operation or the engine operating in a 'default' safe mode.

By the model year you've given, it should be an OBD-II system. Places like AutoZone will pull the codes for free.

As far as the sputtering problem, as JohnM mentioned - a shop-performed injector cleaning may be in order. Some other ideas are a fuel system priming problem, or an injector leaking down while the engine is Off.

2500rpm sounds kind of on the high side for shifting if fuel economy is your goal.