To lean please help

[sonic_03gt]

First off i am a new member. And i absulutely love this site. I have been looking for a forum for a few weeks now. But any ways, My car is coming up to lean on both 02s. And it kinda seems like it wants to rev up and down on its own....Not bad or nothing maybve jumps around 2-300 rpms. Does any one know what would cause this? It runs great while on the gas...My gas mileage seemed to drop real bad tho? My mods are n my sig I am new to the ford world and have always been a camaro guy. Any help would b gretly appreciated. Thnx guys.

 

[98COBRA281]

for some reason you sig is not working, can you post up your mods, and has yuor car been tuned?

 

[sonic_03gt]

I bought the car with most of the parts all but the wheels springs gears and the shifter. When i got it ran perfect with the mods it had. So i am guessing some kind of tuning has been done. but idk?
slp longtubes
slp o/r x
sp lm1
bbk cai
4:10s
eibach pro kit
steeda ud pulleys

 

[RedDaemon]

what octane do you fill up your car with? if its not a cobra, GTs take 87.

if you just filled the car up with a lower octane this could explain why yours running lean.

 

[DBMSTNG]

is there a K&N filter on the CAI? if so, check the maf to see if there is any filter oil on the sensor. if so, that could be causing the problem.

 

[sonic_03gt]

I have checked for vaccum leaks and exhaust leaks. Changed the fuel filter and cleaned the maf sensor already. I just dont underst7and why it would b lean like this all at once?

 

[GoBabyVroommm]

Well i'm going to say its o2s. If you have a stick car you won't notice bad o2s but if its a auto car it sucks. But then again, if your o2s are out the computer makes your car run very rich so you don't blow your motor.

Another idea is that your pump might be going out. From my understanding that 99-04 pumps work a little harder then the return system pumps.

Just puttin my 2 cent in hope it helps.

 

[sonic_03gt]

Would both go bad all at once tho?? I mean i guess that kinda makes sense bc of gas mileage.