Engine Revving

Maybe I didn't make the focus of my question clear-or I'm not understanding your answer. Why does my Explorer just stop running while driving (usually after 20-30 miles of steady driving) and it happens when the outside temps are warm to hot, but not in cooler (below75) weather? "Check Engine" light doesn"t come on. What could be happening in the mechanics of the car to create this problem? Why doesn't a Diagnostic or Scan show anything when I bring the car in to be checked? Again, Help, Help, Help. I had to cancel a trip this weekend because the weather is not quite cold enough for me to feel confident that my Explorer will get me from Point A to Point B.

OBDII scan codes
P0135, P0141, P0155, P0161
P0743, P0750, P0755, P0760, P0765
plus 1451 and 1747

O2 wires look OK (all four)
Lever shifts on side of tranny when put in gear

Car stalls in each gear
Starts fine, revs fine in neutral

There was a high pitch sound from under the hood. It was consistent from when I start it, idling (not as loud), to accelerating (got louder). At one point coming up the hill, sounded like it was crackling/rubbing until something broke/snapped. I looked in the review mirror and saw a circular piece rolling. Tried to look for it but couldn't find it. Any thoughts?

Engine Performance problem
2003 Ford Explorer 6 cyl Four Wheel Drive Automatic 103k miles

While idling in park, about every 5 seconds, my RPMs drop from around 900 to 500. I also, hear a click coming from the engine when it happens. Sometimes quits when I shift from drive to park.

I find some ford products are bad for this and I feel you may have the same problem. If you remove the plastic cover from the top of the engine you will see a cylinder looking thing that sits higher than anything els. It sits kinda at the back in the middle, there will be a plug from which you will see wires. This is the air bypass valve. What I have done with two different fords is, Have some one hold the brake with it in drive or keep it in park, you want it to run rough or at low idle. When you do this take a small wrench or screw driver and tap on the air bypass unit, you my want to tap hard because it may be stuck. If this is the problem the ford will rev nice after you tap the part. Two screws hold it on and it is never found on the computers in the garage. 100 bucks for the dealer part but worth it. Hope this helps.

Vehicle began to buck at certain speeds/rpms. Once it begins to buck, I can adjust the pedal to either slow down a bit or wiggle the pedal and then accelerate to where it kicks into passing gear and the bucking goes away. But once I'm in that 1800-22000 rpm zone, it will do it again. No codes. In fact, the only code ever to come up was the Evap cannister has a small leak and pops on once in a while.
Otherwise truck is very quick and strong. Drove it like this to South Carolina and back and got great gas mileage. I replaced the IAC pump, the plenum gasket, cleaned the throttle body and flange, changed the plugs and checked the wires the best I can. Any ideas? Thank you for your time.
John

Was fine and stopped at a red light and this problem occurred.

Last week?About truck has no power. No codes, fuel pressure 60psi, check exhaust pulled convters off no change, tps tested good, maf new, conpression test 125 on one cyl, vac test 18 at idle runs good at idle up to about 2000rpm drives no power no back fire clean exhaust no smoke?Help