Ok, im gettin an average of about 10 mpg, with mostly highway miles. My fuel filter was just changed, cat was put on a little over a year ago. new ngk tr55 plugs ad msd 8.5 superconductor wires, both installed about 4 months ago. Exhaust wise im runnin eddlebrock shorties, to 3" y, to eddlebrock 3" catback witha 3" dump. Anyone have any suggestions? Its killing my pocket.

 

Sounds like you either need an injector cleaning or a sensor tune up.

Check to see if the vac line to the FPR is wet. If so change the FPR cause it's dumping fuel into the intake.

If that's ok, check the fuel pressure when the engine is turned off. See how fast it goes down.

Since your using a cotton air filter, try cleaning the MAF. Many people put too much oil on the filter and it contaminates the MAF.

The last thing is to check the sensors to see how they are acting. Like the MAP and the O2's.

 

what do u mean by a sensor tune up?

 

Things like oxygen sensors start to become less effective after about 50K miles. I think he means you should make sure all sensors on your car are working as they should. Bad oxygen sensors will most certainly be one cause for poor fuel economy.

Greg

 

Wouldnt o2 sensors throw the ses light?

 

Not always. Over time, the oxygen sensors will become coated with carbon and other deposits, which will cause them to give wrong readings to the ECM, however, that situation will not throw a light.

Greg

 

ok, i thik im gonna change them, thanks

 

Can a carb and choke cleaner be used to clean the MAF?

 

one more question, where are the o2 sensors located

 

On your car they are located at the bottom of each exhaust manifold.

Greg

 

No, I wouldnt use that. I use electric parts cleaner (Autozone) and you dont even have to touch the wires on it. You just spray it and you see the dirt coming off of it. Some people use Q tips, but be VERY careful.

 

you probably have an exhaust leak with the addition of the headers. dont go out and spend money on sensor you arent positive are bad... that is waste of money. instead do some investigating around the collectors and header flanges for signs of carbon deposits. if the leak is bad enough you could even hear it making a "putt-putt-putt-putt" sound in sync with the exhaust pulses.

 

anyone have a pic of the location of the o2 sensors and the fuel pressure regulator

 

Both your picture requests can be found here:

http://shbox.com/1/4th_gen_tech1.html

Credit to Shoebox.

Also: I'd have to agree with turbo_Z -don't spend money on parts that aren't confirmed bad. Ask me and my *still* 10 MPG car how I know this doesn't work.

 

Well, o2 sensors arent that bad in price so i figure i'll just pick two of them up, then i figure I'll upgrade my injectors and throuw on an ajustable fpr. Oh and ts not an exhust leak, the headers have been on the car for a couple years, the problem just started like 2 months ago and keeps gettin worse.