This sounds similar to the problem I'm having. Is it a rough jerky popping type of miss like a short or is it more of a smooth bog type of miss as in loosing power like it's not getting fuel or a rev limiter kicking in?
Here's the thread I already have in this section:
Loosing power @ WOT above 3000 - need help
Looking for some diagnostic help on my ’95 GT 93,000 mile 5.0 motor with a stock intake system (except for
K&N filter) and a Mac shorty /
Flowmaster cat-back exhaust. In other words, a basically a stock original motor w/o many mods.
The car runs great except above 3000 RPM at wide open throttle. About 2000miles ago I had some intermittent stating problems so the fuel pump, idle air control valve, ignition control module (not the computer), ignition coil, and fuel filter have all been replaced. (Replacing the ignition switch finally fixed the problem….). The car has been fine up to about a month ago.
For normal everyday driving the car is fine. If you run it up to 4500 at part throttle it’s fine and it will run continuously (cruise) at 4500 without a problem. It’s when you punch it and try to rev it above 3000 RPM that it has a problem. In other words, it will run up to 4500 fine with a part throttle but if it’s WOT (floored from a take off) it will run up to 3000-3500 RPM and then act like it’s running out of fuel above approximately 3000 RPM. It will start to die and loose power at 3000-3500 but momentum will carry it up to about 4500 (starts acting up about 3000 but will still rev up to 4500) but by then it’s dying enough to slow itself back down. If you hold it WOT it will continue to slow itself back down just like it’s running out of fuel. If you back off to part throttle at any point it’s fine and will run at 3000, 3500, 4000, what ever you want, but as soon as you step back down to WOT it acts like it’s loosing it’s fuel flow and begins to die again.
No check engine light is showing and the fuel pressure regulator seems to be operating ok (I have a fuel pressure gauge mounted on the rail and at idle the PSI bumps up with the vacuum line disconnected like it should). With a new fuel pump and fuel filter, new ICA, and new ICM in the car and the regulator appearing to work I don’t really know where to go from here. It strikes me as a computer control/signal issue or some sensor like maybe the throttle position sensor type issue. I just hate to just throw money at new parts (particularly the computer) and hope something fixes it.
Anyone had this problem and know how to fix it!
Thanks.
Follow up coment: This feels more like a definite cut out though, more than just a miss. Like a loss of fuel or the timing is being pulled waaay too forward or something. Almost like a rev limiter is kicking in earlier than it's supposed to be. Seems like either an RPM, vacuum, or computer controlled thing because letting off the gas will allow it to pick back up but as soon as you go back to WOT it will want to die again.
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95 GT w/ stock 5-Speed and 3.55 FRPP gears. KB underdrive pulleys. MAC unequal length headers with Flowmaster catback and stock cats/H pipe. K&N filter. Aluminum clutch quadrant.
Hurst Billet Plus shifter w/ HD clutch. Stock heads, intake, and TB. 95 Cobra 17x9s w/ Toyo Proxes. Pioneer 550 watt w/ 10" sub.
66 Mustang Convertible. Owner since 1979. Original code 76C bench seat convertible. 289 4 barrel. Automatic. 3.25 Trac-Loc. P/S. P/B. A/C. Power top. Rally Pac. S/S wheels.
Does my problem sound the same as yours or similar but not exactly the same?
Just wondereing, still haven't figured mine out........
