Random Power Loss at Highway Speeds

[Mikey1968]

OK....cruising at 75mph, push slowly on the pedal to do a slow acceleration and then total loss of power....coast to 60mph and power kicks back in like nothing happened. One time, on cruise control at 75mph and does the power loss without me touching the pedal. When it happens, the tach stays pretty close to the same rpm so I'm still thinking a fuel problem.

Things worked on....Cleaned the 10-pin connectors, new fuel pump, new TPS, cleaned EGR valve and throttle plate, new EGR sensor, new distro/TFI, new fuel pump relay, cleaned MAF sensor, timed engine, pulled codes: all good, fairly new timing chain, new Bosch platinum plugs, new fuel lines from pump, new fuel filter, new gas tank and Ford Racing wires.

Stang is a stock 89 GT with a new T5 and K&N air filter.

I went ahead and checked my fuel pressure with the old regulator on and here's what I got:

Idle - vacuum line off: 42
Idle - vacuum line on: 35-36

While out of gear - accelerated engine rpm - vacuum line on: Instant 40-42 then drop and held at 34

Key off it held 40

Looks like the pressure is a bit high.

I bought a new OEM type fuel pressure regulator to put in but haven't had time yet. I've run out of ideas.

Any help would be appreciated. Yup, this is a summary from an older post....still not fixed!

Thanks in advance!
Mike

 

[Mikey1968]

ANYBODY????

Can someone give me a source for a data logger? Since I'm not setting any codes, perhaps I should attach a data logger to the computer?

 

[vristang]

Probably a good $500 for a datalog system...


There aren't ANY diagnostic codes?
OR
You get code 11 for system pass?



jason

 

[Hickfied]

Maybe the clutch slipping? I have a 93 4cyl notch, that when the rpm's get right at 4k, it seems to lose power. I just figured the clutch is about to go. It will pull great on the highway, untill exactly 4k rpm, and then it feels like it hits a wall.

 

[Mikey1968]

Clutch is fairly new....I used OEM Ford clutch.

Is that datalogger the Tweecer I've read a little about????

I can try to pull codes again but the only code I've gotten is the one on the clutch switch as I keep forgetting to run it with the clutch in or something.....

I'm totally frustrated!

 

[bsedwebt70-5.0]

sounds like the HALL EFFECT inside the distributor is going bad - mine did that - I replaced the ignition module on the side of the dizzy but it did not cure it until I replaced the WHOLE dizzy from Autozone - get the STEEL drive gear for roller engines

 

[Mikey1968]

sounds like the HALL EFFECT inside the distributor is going bad - mine did that - I replaced the ignition module on the side of the dizzy but it did not cure it until I replaced the WHOLE dizzy from Autozone - get the STEEL drive gear for roller engines

You are correct....however the distro is brand new....got it from Car Quest (pretty good parts).

 

[Mikey1968]

Humpf! I haven't tried changing the coil...new one is now in so stay tuned....I thought I had changed it but was thinking of my other 5.0L.......duhhhhhhhhh!

 

[Mikey1968]

I've driven it a few times now and tried to get it to stall out. So far so good. I'm declaring victory but it is so random, I may be premature. If it happens again, I'll post....otherwise....seemed to be the coil!

 

[Mikey1968]

Just thought I'd update this...it wasn't the coil as it did it again as soon as I posted my victory post. So I pretty well gave up. T

hen, a buddy gave me his 2-1/2" Flow Master cat-back system since my stock pipes were rotted on one side. He went with a quieter set up. Sooo...I cut out the Flow Masters and kept my turbo mufflers to keep things a little more quiet. The PO had installed the pipes all the way into the turbos basically blocking most of the exhaust!! That was it!

Man, do I have horsepower!!! Hesitation is gone! MPG is up! Mikey Happy!!!!

There ya go! Blocked exhaust!