To continue this thread and my issues, I was coming home last week driving at highway speeds when my explorer completely died. No struggle, no stutter, just died. A new check engine light appeared. I can't remember what the code was but it was something along the lines of the engine reached its maximum lean limit and it wouldn't let the car run. It would fire and stall instantly but would not run. Fast forward to today after I got the upper and lower intake gaskets changed along with the EGR O-ring. I no longer have any of the above mentioned codes but I do have a never before seen P1409 code. The explorer is still running rough at idle and heavy engine load. It will have trouble starting but will fire up and idle like a big cam muscle car, after about 30 seconds it will idle to around 1200 then back down to 850 with a smooth idle. When idling normally if I floor it it will stutter hard until I let off the pedal a bit then it will act normal bringing the rpms up. Any thoughts? I've double checked vacuum line connections and I torqued all bolts on the intake accordingly.
