'97 Expy Power Loss

[givemeabreak]

Recently, while pulling a trailer (loaded with 800# Golf Car) I experienced a situation which could have been disasterous. While on a two lane and attempting to pass an 18-wheeler, with my foot "into it" and passing gear engaged, 3000 rpm and about 67 mph my 5.4L lost power and the mph started "unwinding" dramatically. The engine became very quiet (almost as if it were operating in a vacuum), the rpm showed 3000 and then started dropping off gradually and the mph unwound quickly, down to about 55mph. I braked slightly to allow the 18 wheeler to advance his position in the RH lane and then slid in behind him. The engine "took hold" again after the tranny dropped out of "Passing Gear" and I was able to accelerate normally back up to about 67 mph. Curious to see what would happen, and with an open road ahead, I again engaged passing gear at about 65 mph and almost instantaneously got the same results; increase from about 2200 rpm to 3000, very slight increase in mph to about 67 and then the power loss. Rapid loss of mph and noticed rpm appeared to be "fixed" at 3000 rpm and then started dropping after about 3 - 4 seconds. Let off on the accelerater and power is restored and acceleration becomes normal so long as you don't engage "passing gear." I might add when the power loss occured you could detect a slight chatter or clatter on the foot feed and in the entire car body as if the engine was misfiring. I've had COPs (4 to date) go bad and this DID NOT feel as severe as when one of those Coil Packs fails and the whole car starts shuddering. I DO NOT have any Check Engine light on or anything that would indicate there's a distinct problem with a sensor, plug or fuel injector. Any thoughts out there? Thanks to all. If you can't help I guess I'm back to the "$500 (minimum) a trip" to my local Ford Dealer. By the way, I have the full set of Service Manuals for this vehicle and can't find anything in there to help me search and resolve my problem. This truck has 106K miles on it and plugs were replaced (at least I paid for them) 30K miles ago. Thanks again.

Update: 4/13/07 - Bit the bullet and took it to Ford Dealer. Appears I have a bad MAF and Faulty PCV Tube. Cost me $90 to find this out and for a mear $463 more they'll fix it. I respectfully declined and will attempt to do this myself with the aid of my Service Manual. Can anyone direct me to the person / organization who has posted on this site their offer of Ford Parts at discount? Thanks. I'll keep you posted on whether replacing these parts fixes my problem. Stay tuned.