Engine Running Lean, Tried Almost Everything, Help!

[jlindo827]

Hey everyone, I'm at a loss on my issue with my 2002 Explorer 4.6l... I'm running lean on Bank 1 and 2 (P1151 and P1131) and getting random misfires along with the truck not wanting to stay running at idle. When cold it will run ok for a bit, but then I'll be at a red light and the engine will Rev up and down and will die out unless I keep my foot on the gas.

Here is what I have done so far:

- Replaced all coils and plugs
- Replaced MAF sensor
- Replaced fuel filter (and checked fuel pressure at the rail and everything was good)
- Replaced EGR valve
- Checked for vacuum leaks thoroughly (used a smoke machine) and I had already replaced the infamous elbow when I had a similar issue a while back.
- Replaced the upper intake gasket and inspected the upper intake while it was off for cracks etc.
- Replaced the PCM

I've done all of this and nothing has worked. I've read so many threads, articles, watched videos, and googled everything possible. I've asked mechanics at work and they are at a loss as well.

Hoping posting this here will maybe spark something I haven't tried. I dropped working on it for about 6 months now but as Spring is rolling around I want to get this truck running right again. My next guess would be to actually try replacing the upstream O2 sensors. Funny thing is they read correctly with live data then all of a sudden drop off to about .0025 volts.

Let me know what you think, it would be greatly appreciated!

 

[jlindo827]

Hey everyone, I'm at a loss on my issue with my 2002 Explorer 4.6l... I'm running lean on Bank 1 and 2 (P1151 and P1131) and getting random misfires along with the truck not wanting to stay running at idle. When cold it will run ok for a bit, but then I'll be at a red light and the engine will Rev up and down and will die out unless I keep my foot on the gas.

Here is what I have done so far:

- Replaced all coils and plugs
- Replaced MAF sensor
- Replaced fuel filter (and checked fuel pressure at the rail and everything was good)
- Replaced EGR valve
- Checked for vacuum leaks thoroughly (used a smoke machine) and I had already replaced the infamous elbow when I had a similar issue a while back.
- Replaced the upper intake gasket and inspected the upper intake while it was off for cracks etc.
- Replaced the PCM

I've done all of this and nothing has worked. I've read so many threads, articles, watched videos, and googled everything possible. I've asked mechanics at work and they are at a loss as well.

Hoping posting this here will maybe spark something I haven't tried. I dropped working on it for about 6 months now but as Spring is rolling around I want to get this truck running right again. My next guess would be to actually try replacing the upstream O2 sensors. Funny thing is they read correctly with live data then all of a sudden drop off to about .0025 volts.

Let me know what you think, it would be greatly appreciated!

View attachment 449785

Also Replaced the IAC valve.