Hey FTE Guys,

So I purchased this truck from a gentlemen up in Wyoming, the engine is a 7.5L 460 EFI rebuild with 75k miles and the truck itself has about 218k miles driven. I noticed it needed a tuneup and so I got started.

The first thing I did was redo the exhaust from the Hedman headers that were installed when I bought it, to the original CATs and out to Thrush Glasspacks.

I then re-did all the spark plugs with Motocraft Platinums, I'm assuming they were pre-gapped due to them being the original plugs. (0.44). I checked one of the plugs and it showed a snug 0.44 gap.

I re-did all the tubing from Diverter Valve to the exhaust and from the smog pump to the diverter valve.

New O2 , MAP sensors, Spark plug wires and K&N Air filter. I also re-did all the plastic vacuum tubes to some good rubber vacuum lines, all the TAB lines to the EGR and to the canister.

The Vacuum pressure is about 17in Hg (I live in Colorado), the spark plugs are all getting a strong blue arch, I couldn't see any jumping. I quickly listened to all the injectors which seemed fine and ticking.

The KOER test only returns code 41 and nothing else. I first noticed issues after I did the spark plugs & diverter valve tubing, when I started her up, it sounded like she was struggling in idle after first starting, dropping low then coming back to a solid 600 RPMS and staying there. There seems to be a smell of gas fumes in the exhaust and sometimes a slight stutter or maybe small backfire (really quiet backfire).

What I'm not understanding is why it's reporting lean with rich symptoms or maybe I have the completely wrong idea.. Who knows, I'm a computer engineer by trade.

The truck ran fine until I redid the diverter valve and spark plugs, I can't tell if I maybe caused a wire to fatigue and break or if something is wrong with the spark plugs, I am not sure. I was hoping someone could shed some light on possible issues.

Thanks!

P.S I have been searching this issue for a solid two weeks, I'm willing to take videos and pictures if necessary, I just want my baby running right!

 

You did not say what transmission you have. If it is the E4OD then you would not have a two digit code but a three digit code.

Also with the Hedman headers the O2 sensor is in the the wrong place and will give a code in KOER self-test and needs to be moved it you do not have it in the cross over. But it is not the lean code you get if it is in the wrong place.

 

I have a 5 Speed, I'm not sure the model of the tranny, I will look.

I took a video of the miss fire sound , I will try and post it later. I'm gonna pull all the plugs today and check them as a good first start.

I am definitely getting 2 digit codes, It goes "4' long pause "1" long pause then spits out 41 and repeats 41 again on KOER. I will do a KOEO test next and see what that pulls.

 

So I went and had the codes pulled fully and it returned everything was okay on KOEO and then KOER returned "41 System - Lean Right Side" but the problem is I only have one o2 sensor on the passenger side after the CAT. I am starting to think that the EGR / Diverter valve is dumping too much air into the exhaust and causing it to think it's lean, over fueling the mix but still reporting lean.

 

What about the CM codes? are they returning a 11 also.
If the CM codes report a 11 this would mean that you are not running too lean while running only during the KOER self-test.

 

KOEO/CM is returning System OK and nothing else, it doesn't give me any codes at this point.