Hey gentlemen, I'm looking for advice I've been searching through the forum for answers but haven't found anyone with similar issues. My truck has about 93,000 miles on it. I recently returned from a 6 month deployment and had friend taking care of my truck, it was driven at least once or twice a week while I was gone. A few days ago while driving in SoCal traffic it began to lag and stutter a few times around 40-45mph. Once traffic speed up it has driven fine sense, but still have the CEL on. I bought a code reader and received P0171 (bank 1) system too lean), P0420 (bank 1) catalyst efficiency below threshold, and P0430 (bank 2) catalyst effciency below threshold. Any guidance will be much appreciated.

 

A lean code does not mean the motor is running lean, it only means the computer has "detected" a lean condition. In which it will up the air/fuel ratio to compensate. On the other hand the cat codes means the cats may be on their way out, caused by the rich fuel mixture.

Find the cause of the lean code first, probably a bad vac hose.

On the cats, that is an expensive proposition in calif. I think the state mandates that the cats are to be covered under warranty until 100k miles, but I could be wrong. If the cats are bad have them checked out at a good dealer to see if they are indeed covered.

Good luck and let us know how it turns out.

 

Well I wound up swapping out my K&N filter for an AMSOIL filter on my COI and cleaning the MAF, and lean code went way. About 2 months later I got a cylinder 7 misfire, codes for cat below efficiency for bank 1 and 2, and code for bank 1 too rich. The exhaust smelled like a mixture of rotten eggs and strait fuel. Since the truck is 11 years old I swapped out all of the spark plugs and coil packs, I found some great tips here and didn't break a plug. I let the truck for for a couple minutes to burn out the carb and choke cleaner/pb buster that dripped into the cylinders when I swapped the plugs.

I went ahead and changed out my cats and put in new O2 sensors. I let the truck run for a few mins it sounds better than it ever has, but the exhaust still smells of fuel. I'm not sure if its just any residue in the pipes from manufacturing or if its an injector issue. I don't want to keep throwing parts at it, I'm already $1400 into this fix.

 

The 05 5.4's did have a known injector issue. They were leaky and could stick open.

 

My 04 5.4 CEL came on and code is P2195 . Is there any way to check and make sure it is an o2 sensor?

 

Read this:

https://www.obd-codes.com/p2195

 

Thank you! Ordered a new NTK 22524 sensor,hope it works.