2004 Fx4 5.4! Need a little direction! I get a CEL about once a week that's telling me the truck is running rich, but the light stays on for a couple days then goes out only to come back again in a week! The dealer tells me it's my coils, plugs, O2 sensors, or maf sensor! Everything has been replaced but the light is still coming on and going off every couple days! Before I take it back and have it diagnosed again for $100.00 I thought I would get everyone opinion as to what it might be! Oh I did replace 1 faulty injector a few months back! The truck runs smooth with no engine miss!

Thanks guys,
Jacob

 

You can have your CEL code's red for free at Auto Zone...

 

Should of mentioned that is where I get it checked, but when I take it to the dealer they check the codes to before they tell me what might be wrong, and they still charge me for it! I keep getting the same code!

 

Well...if they changed all that stuff and it still don't run right...I would take it back to them and make em fix it...good luck

 

Well I did all the work to the truck they just told me what it could be! It's still on me if I let them tear onto it! Which I don't really want to do, but might have to!

 

Could be that injector you replaced (or another one of them for that matter) has gone bad and/or is leaking a little bit causing more fuel to be injected into the cylinder. If your engine really is running rich than watch out for those cat. converters as they could go bad due to too much fuel.
If truck feels like it runs fine it could be something sensor or PCM related but I dono. Maybe something valve related? There's so much it could be; looks like dealership guys are just trying the cheapest thing first and working up from there (although they charge a lot for replacing plugs so go in there bitching and maybe they'll do some stuff for free...maybe).

 

I'm gonna go there and b**ch see what they tell me!

 

Hello brother Jacob
I know this is a truck website, but I've pondered all the same possibilities with an '03 Crown Vic. No CEL but sometimes feels like your trying to pull a house. It will change back & forth from bad to good while driving it. Mine also is smooth with no misfire.
Some soot noticeable in tailpipe. Dealer has no idea. Their only comparable is several police cars with leaky intake gaskets, but they all set codes. The way this goofy OBD stuff works, who's to say that the system might not load the engine up with fuel to compensate for a significant vacuum leak. Who knows? Might be worth getting a scan tool that gives live data, not just codes. Got mine for $140. at Princess Auto, (probably your equivalent of Harbor Freight) Glad I saw your thread because O2 sensors and MAF sensor were my next experiments, even though O2 sensors seem to be toggling properly and fuel trims are within spec. I've also wondered about injectors. Changed plugs, all 8 coils, did motorvac & serviced trans. Better but not great. Hopefully, watch scan tool long enough, some light may dawn. I'm thinking might either have to live with it or bail out. If your performance is ok, maybe CEL not worth worrying about. Good luck with it.
Mike