My check engine light came on while I was out of town of all times. I had the code read at Autozone and it said that both banks were lean. After arriving home I cleared the codes and drove the truck around some more and sure enough the CEL came back on and gave the same codes. My truck is an 02' and it is very stock. I'm changing the fuel filter right now but the truck doesn't behave like its got a clogged fuel filter. Anybody got any ideas on what could cause this? On cold start-up sometimes I have to give a little throttle to keep it from dying. Perfect otherwise.

 

You are on the right track. My truck did the same thing and didn't act like a clogged fuel filter, but changing it did fix the problem. For both banks to lean at the same time, that is what my guess would be. Come back and let us know if that fixed it or not. The next steps would be cleaning the MAF, check for vaccum leaks and other simple things like that.

 

Thanks for the info John. I got the fuel filter changed and I reset my CEL. I'll drive it around a bit today and report back.

 

could be a loose or damaged vacuum hose, the one behind the lower intake manifold rots out I have heard and it near impossible to reach without removing the blower.

 

Yep i had that problem too, but with 122k miles you start having some small issues. When that happened though the truck would idle high, about 1k in park and would run like poo. I finally changed it out when i replaced my supercharger. I couldn't get to it without removing it.

 

sounds like an air leak to me.

 

Been there done that and it ain't no party. I read where some have been able to reach down there and replace it... no way unless you're Gumby.

Pull the SC and the upper intake and pull the intercooler too and clean it. Reach back there and yank hard on what is left. The replace with a quality fuel line. Send me a PM if you need the instructions for R&R of the SC, upper intake and the cooler.

Plan on an afternoon or better.

 

This sounds like a job for my extended warantee.

 

I assume the codes came back ??? Bummer....

I know these codes and had both on the GT when I first changed Maf's.
The Codes are very common with a Stang after installing a SC and changing to a Blow Through Maf set up. The fix is simply turning the Maf to diff positions; 12:00, 3:00, 6:00, 9:00... I eventually found the happy spot and never threw another code.

Did you do anything that changed the orig Maf set up recently ???
Changed the Intake ? Filter ? added a CAI ? changed the Maf or position ?
Rememeber the truck will also run with no Maf, I had to drive mine to Sal once without it even hooked up (all kinds of codes came up including yours).
So of course check your maf plug, check the Maf itself and make sure it's not dirty or the filiment isnt broken. As said maybe a Vac line could do it, 02sensors, smashed fuel line, bad gas clogged the injectors, the list goes on and on... BEST OF LUCK

 

Hey Rob.
No I haven't done anything to it. I'll investigate the MAF and see if its dirty or if the plug is loose. The codes didn't come right back. I drove around a bit and I got a BANK 1 LEAN CODE. I reset it and it came back a little later. I reset it again and haven't seen it yet again and I've been doing a bit of driving so maybe its finished with its hiccups. I haven't seen the BANK 2 go lean since the fuel filter change. I'll be on my Ps and Qs for the next few days to see what happens. Later guys and thanks.

 

hey, same thing happened to me before.. tried everything you did and the cel always came back. It ended up being the vacuum hose that goes from the passenger side valve cover to the back of the lower intake. I bought the hose assembly at the dealer(it was cheap) and replaced it without taking off the blower.. It wasn't easy but i've never gotten the light back.. good luck and you can pretty much rest assured its that..

 

I will certainly look into that. Thanks.

 

Im a parts sales manager for AutoZone and I'm not a mechanic, but I have worked for the company for five years and have seen the same codes so many times. Im pretty sure if its both its going to be a mass air flow, although I have seen oxygen sensors triger such a code. Try disconnecting the battery and letting it sit for about 15 minutes, spray the mass air flow sensor(the little sensor that stick in through it) with some fast drying electric cleaner, and then reconnect everything.

 

OK guys codes showed back up today. I'm gonna clean my MAF and inspect the hoses for vacuum leaks. I'll let you all know what I find.

sadf, I wouldn't think that all of a sudden I'd simultaneaously get two bad O2 sensors AT THE SAME TIME. But the MAF could be the culprit. I thought that the MAF would throw it own code tho. Anywho I'll be looking into it a bit further now.

Thanks everyone for their input. Updates will follow.