144kenneth

I have a 1993 mustang summer edition 5.0
This thing has been a nightmare and I am at my wit's end.
I finally got the surging idle fixed and the constant burning out TFI module (moved to fender ) but now it misses and cuts out badly at light throttle, according to my wife who is the primary driver, It died 4 times on her 20min commute ...
So far in the past year and half these are the parts I have
Replaced and things I have addressed-
Tfi module.
Cap and rotor.
The stator located in the distributor.
Plugs and wires.
O2 sensors.
Vacuum lines.
Fuel filter every 2-3 oil changes.
Idle air bypass.
Throttle position sensor.
Ignition coil.
Cleaned all engine harness grounds.
Checked timing.
New fuel injectors.
Fuel pump relay.
I don't know what else it could be but a failing fuel pump, but it starts and idles great and goes good when you floor it, it just shuts out at mid throttle
Any ideas??? I'm all out

dawson1112

Try cleaning your MAF sensor,


Pull codes to see if any thing is stored in the computer.

88 orangepeel notch

+1 ^^^.

Then do a sweep test on the TPS, looking for and spikes/dips in voltage reading.

144kenneth

UPDATE.
Replaced MAF tested new TPS (good) and replaced ignition module.... Still the same issues and it's getting worse

dawson1112

did you check for any stored codes?

mjr46

tap into the fuel pressure port and run a gauge to the windshield and see if it is loosing pressure when it dies to rule out a fp issue

144kenneth

Rookie mistake... I had the switched 12v for the fan wired to the positive in my coil, just weird because it's been like that Months and had no issues, it only started randomly shutting off lately. Also Still going to replace the fuel pump back to OEM, I don't trust that walbro 285 I put in it when I bought it. Any way, I need to drive I've some more at the random **** thing took a while to happen some time. But the hesitation at mid idle seems to have cleared....
I'll keep everyone posted on it.
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144kenneth

after my last updated, I took it on a good half-hour drive and put it through its paces, it ran better than I can ever remember. But then just after I turned around to come it stalled in the exact same way again.... I stopped and put in a new starter solenoid (last thing I could possibly think of) in it and had the codes read again and I'll I got was a code from my charcoal canister that I had plugged off due a rotted vacuum line from the intake.
aside from a wire harness issue, I have literally no clue what else it could be.

144kenneth

after my last updated, I took it on a good half-hour drive and put it through its paces, it ran better than I can ever remember. But then just after I turned around to come it stalled in the exact same way again.... I stopped and put in a new starter solenoid (last thing I could possibly think of) in it and had the codes read again and I'll I got was a code from my charcoal canister that I had plugged off due a rotted vacuum line from the intake.
aside from a wire harness issue, I have literally no clue what else it could be.

mongolchuck

When you say you replaced the distributor stator are you talking about the pickup aka pip sensor? Check your grounds again, especially the ones for the computer, and check the eec relay. Start it cold and run a hair dryer on it to heat it up a little, not plastic melting hot, and see if it fails. Just remember a tight ground doesn't mean good. We're talking about cars that are 25 to 30 years old now and a little corrosion can cause big problems.