1995 Mustang GT Power loss with WOT

misko said:

When cold runs great no problem. After warming up to normal operating temperature with new 180 thermostat my 1995 Mustang gt looses power when accelerating hard while parked or driving @ 4000-5000 rpm. I have replaced the ICM, Mass Air Flow Sensor, the Engine Temp. Sensor, Coil, and Fuel Filter, all to no avail. I am stumped. Could the PIP cause this problem? Any help on this matter is appreciated. Thanks .

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check engine light ? / fuel pump maybe ?

when mine threw those codes it was a dirty maf. but you say thats new. did you unplug the batt after replacing all those parts? the puter needs to relearn the right info. the dizzy or the fuel pmp could also cause that issue.

misko said:

The only codes were Lean bank 1&2-------Fuel pump pressure shows 41psi.

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have you checked it while driving ?

misko said:

The only codes were Lean bank 1&2-------Fuel pump pressure shows 41psi.

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was that checked with the vacuum line off and plugged ? or with the vacumm line still on the FPR

if you think the PIP is bad easiest thing to do is to get a reman distributor at advance or autozone

One quick thing would be to check the voltage on your TPS to be sure it's around 1 volt closed and above 4.25 at WOT. (double check those voltages, please correct me if I am wrong.) -- Contrary to what many say, you DO NOT have to poke a hole in the wire to read the voltage of many Ford sensors. Where the wire enters the harness is rubber, put the end of a voltmeter up the harness parallel to the wire pushing the rubber out of the way until you get a reading.

Serious question, did you replace the engine coolant temp (ECT) sensor or the temp sending unit for the gauge? They're different... I only ask because a dude a Autozone tried convincing me the two sensors are the same...

It sounds like you have a problem when the car enters closed loop. If your MAF is good your 02 sensors could be causing you a problem. If they're old or have 80K+ miles, I would replace them.. But before you throw money at it try this: When your car is COLD to the touch, like in the morning or after many hours of not running. Start the car and let it warm just enough to make sure your oil is flowing and get on it. Take it up to where it usually falls off (4K-5K), just becareful because you don't want to take it to redline with an engine that isn't fully warmed to op temp. You want to make sure you get on it before the computer enters closed loop. If you do not have a power loss then it is an open/closed loop problem. If it is, usually that means bad 02s or MAF. Post your results.

any misfire codes? fuel pressure is constant? or is this a scanned reading? a scanned while driving reading? a continiuos scan while driving is needed but I agree that it's a fuel supply issue, maybe a pinched return line or supply; high pressure doesn't mean high flow, usually just the opposite.

check your o2 sensors. if you dont have a scan tool an easy way to find out is to unplug the o2 sensors and than take it for a test drive they are located between the headers and the ca