93 Crown Vic 4.6L OHC

Is there a check-engine lite on?

it appears under hard acceleration then disapears.

Kind of odd.

It would probably be worth having the codes checked. AutoZone will do it for free in hopes you will buy whatever they tell you to replace. I can't quite figure why removing the plenum makes a difference except that it removes the MAF... The symptoms could be caused by a clogged fuel filter. They aren't awful to replace and don't cost much. If you haven't done it yet, it's time to do it anyway. It's in front of the rear wheel, drivers side.

I had some strange drivability problems and finally found a hole in a PCV tube. The PCV valve has a rubber tube connecting it to a metal tube but there is another small piece of rubber farther along. Mine had a bend in it and had opened. It was almost impossible to see but I heard the vacuum leak. A new tube made it run like new. It drove me nuts trying to figure out, tho. (I have a '95 CV)

PoD

Thanks PoD,

Well that's twice......someone else also suggested that I might have a leak in my vacuum pvc hose somewhere so that makes sense to me. I haven't had time to check it out yet, but will do soon.

Thanks a bunch!