red302

I own a 93 GT with 46000 original miles. During the past 3 weeks I've noticed a loss in power at about 3500 or 4000 RPM's when accelerating at WOT, but it is intermittent. Today I tried to duplicate it and it was so bad I heard the engine making a difference in sound when it happened. Kind of sounded like it got quieter. All I have done to the engine is put in a K&N filter. four days ago I replaced the original spark plugs, wires, cap and rotor. It did this before the tune-up also. I installed Autolite plugs, MSD wires and the cap&rotor from NAPA. I would appreciate if anyone can help me out with this problem.

gspfunk

Did you get the firing order right?

red302

yes I got the firing order right and it started doing this about a week before the tune-up. But won't messing up the firing order cause the car not to start at all?

5.0_PR

If the wires are crossed, the car will still start but will backfire and run like crap.

You might have to check your timing and go over your past work to make sure you left nothing undone. Maybe a vaccuum hose is disconnected.

My egr was frozen in the closed position so I pulled it out and ran brake cleaner through it and now it runs like a top. I also did motorcraft plugs and cheap wires.

red302

I rechecked my wires and they are all secured and I checked my timing last week and it was at 10 degrees. I checked my TPS this morning and it was at .90.
I tried to move it to .98-1V but I could only get it to .92V. The sensor did not want to turn anymore. I don't know if I am doing something wrong or if something is wrong with my sensor. I have talked about this loss of power problem with other guys with Mustangs and they told me it seems more like a fuel related issue. This car has the original fuel filter on it so tomorrow I am getting a new one from Sheehy Ford. I am also going to check my fuel pressure once I find my gauge. As for vacuum lines I broke one for the air pump when I was doing the tune up but I repaired that already

TBird232ci

Sheehy ford? You in MD red302?

When you say it sounds like the car is getting quieter, it sounds almost as if your have a cat going bad.

red302

Yeah I live in Wheaton MD. I installed a UPR catted X pipe in October 2005. I just went for a fast spin around the block and the car ran fine, but I did not do anything except a visual inspection this morning and a TPS check

r.barn

replaced the fuel filter lately?

maybe it's empeeding flow at WOT, with new
high flow air filter maybe you're getting lean
and computer is freaking out.

Liquid_02

I'd check my A/C cut-off relay if the car's air conditioned, seen that problem a few times. And if you're running it with A/C on too of course.

silver91gt

sounds like your TFI module went bad.
it is on the side of your distributor.

if you have full power till you hit 3500rpm then it feels like a BIG power drop this is your problem.