I suppose fuel could be the issue. Its funny you mention that because today when I had the hood open after I turned the engine off, there was a buzzz...buzzz...buzzz... coming from the charcoal canister. Dunno wtf that was all about. However, if it were a fuel delivery issue I don't think it would run perfect off idle, which it does.



Well this 02 has the flange with two studs. I literally rounded off the nuts with my fingers, it was hopeless to get them off. I swear... the only rusty spot on the truck, figures its what I needa change.

mine idled perfect too, the problem i had was under load at higher rpm's, it would fall on its face

Well, its been snowing here and I really did not want to pull the y-pipe off to get the old 02 sensor out. Therefore I tried other stuff. I swapped MAF's, not the problem. Checked for vac leaks.. didn't find any. Unplugged the old 02, didn't change anything.

My buddy who knows EFI much bettern I do, said it looked like my mixture screw (on the throttle body) was turned in quite a bit. We turned it out one turn and it is now idling how it should. CEL hasn't gone out yet and I think this may be masking the problem.... but at least it buys me some time to wait for the snow to stop.

-Scerb

I took the throttle body off and adjusted the TPS. The throttle body didn't look very dirty - there was some carbon the the throttle plate but the walls themselves were clean. Started it up and same problem.

There is no CEL. I have absolutely no idea what is wrong. I don't even really think its the 02 sensor anymore since the problem kept getting worse over a week or so. If it were 02 I would think it woulda gone bad all at once.

Any more ideas??

Thanks,

Scerb

Even though I tried a new used AFM, I still suspected this was causing problems. I tested mine with an ohm meter and the closed position was reading as if it were still open. I took it out and the plate in there was clearly sticking open. I cleaned it out and it seems to be idling good now. Still a little rough, but like I said it always idled rough. So I guess my AFM, as well as the second one I tried, were both dirty <img src="/forums/images/graemlins/rolleyes.gif" alt="" />

Thanks for the help guys,,

Scerb <img src="/forums/images/graemlins/kewl.gif" alt="" />