5.0 falls flat at 4k rpm ?

CPB00GT

Founding Member
Dec 3, 2001
531
1
18
Florida
Lately my 5.0 has been cutting out at around 4k rpm, like there is a dead spot and then picks back up. It only falls flat on its face like this when the car has been running for awhile. It just recently started doing this. I have already put in plugs, wires, cap & rotor, k&n, fuel filter, pcv valve. In another words a pretty complete tune up. I have been running 93 octane lately too as I have the base timing set at 14*. None of this has fixed the problem. Who can help me solve this?
 
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High speed miss after the car warms up is usually the TFI module (about $30). It is mounted on the side of the distributor on 87-93 5.0's.

Be sure to clean all the old thermal grease off and put new on when you install the TFI. The thermal grease is usually packaged with the new TFI. If not, you can get it at Radio Shack if the auto parts store doesn't have it.
 
yeh it is possible the TFI module on the side of the distibutor is going south. they actually cost like $59. I have 3 or 4 of those things if you need one, or two if you want a spare. I posted them for sale on the classified section a while back. 1 is a new mallory from my old mallory efi dist, 2 are used motorcrafts in good working order. drop me an email if your interested.
 
When my 93 was acting like this it turned out to be a bad cat on the right bank. It was clogged to the point when too much exhaust was flowing it backed up in the h-pipe.

just a though

-a