Also check your EGR valve and vacuum leaks. Likely those wouldn't show up on a CEL. Mine didn't and I had 2 major leaks. Watch your fuel levels too. If you notice you're using a ton more fuel than normal, you've got a vac leak.

 

Okay, it's been a while but I finally had a chance to start on this again. I hauled a car on a trailer a while back and it's definitely an engine problem. It becomes very clear under a load. I checked the TPS, EGR regulator, DPFE and all seem to check out. The EGR valve and ports are clear because the engine wants to die when you apply a little vacuum to the EGR valve at idle. I had suspected that the EGR wasn't opening when it should be and therefore a lean condition at cruising speeds. One question, though: I checked for vacuum to the EGR while in PARK inside my garage. I'll get up to 5-7" of vacuum, then an immediate drop with a slight drop in throttle position. Then I'll get about 3". I didn't think there should be any vacuum to the EGR while in PARK. Any thoughts? Thanks.

 

It may be a bad torque converter.

 

i have the same issue with my 2000 expo. no codes, changed the plus,ocv valvue, sea foamed it twice! changed fuel filter, replaced the bad CP, changed tranny fluid, that was not burnt, changed transfer case oil (was blk) change rear u joint... and i still get it on idle and then press the gas on a load...

 

Was there ever any answer to this ? i am having exactly the same problem ?