It's a long-sad story, but I'll try to get to the point. Started my cold (60 F) engine in the morning. I drove five uneventful miles to a traffic light and stopped. As I drove away, the engine felt like it had a governor. I tried to accelerate, but my speed would plateau at 20mph. I pulled into a parking lot and parked the vehicle, but left it running. I revved the engine and it seemed to respond ok. I stepped on the brake and tried to rev the engine, but got absolutely no response from the engine. I took my foot off the brake and the engine responded ok again. I repeated this procedure three times and the funky-brake thing happened each time. I shut off the engine and called for help. After waiting 10 minutes, I started my truck. The funky-brake thing was gone. I left the truck in the parking lot for three hours. Figured I'd give it another try. The truck performed normally until about mile five. I nursed it the rest of the way home. The throttle response acted choppy and random. And now, here I am, stuck. My best guess is the fuel pump, and specifically the PMD (Pump Mounted Driver). The truck warmed up and the PMD began to fail...? I replaced the lift pump about nine months ago. My Service Engine Soon light did not come on. I performed a code scan with my OBD ll PocketScan and got no codes. However, I performed the scan the day after I parked the truck. The suspect device may have normalized by the time I scanned it. I think I'll take the truck out for a drive, and when it starts to fail, then immediately perform a code scan. I've owned the truck for two years and approximately 15,000 miles and have yet to change the fuel filter.
But somebody, please explain the funky-brake thing. Could the PCM (Powertrain Control Module) be the real culprit!? I have had some other, possibly computer-related, problems: Cruise control doesn't work (emissions connection?); Charging system goes off-line on occasion (bad ground?); Tranny shudders in overdrive near the shift point; DRL's (Daytime Running Lights) stopped working; Poor mileage (13mpg). And theres more!!! But I digress. I HATE MY TRUCK

Check your charging system and grounds (all of them). Sometimes when I have had bad batteries or connections, stepping on the brake will seriously dim headlights etc. Also, when electrical system is compromised, I have had a "no shift past 2nd" condition. These suckers are very sensitive to electrical issues.

Welcome to the forum. Read the welcome sticky, update your sig per instructions and check out the FAQ sticky for more great troubleshooting ideas.

Oh and Mark, get a new fuel filter in that thing!

Mark, don't be a hater, try to understand her!

It sounds like the PCM is falling into "limp home mode". THe info that your
charging system goes off line is important. A thorough R&R of all battery
cable connections, and replacement of corroded terminals/cables would
be wise. On my '97 6.5, the voltage occassionally was low, like 12.5V.
After cleaning up the batterywires, the voltmeter stays solid at just uder 14V

Also, changing the fuel filter and checking for good lift pump operation
is important. From the petcock front&center, attach a hose and feed
into a bottle. Should fill 8 oz in less than 30 seconds, and engine should
not cut out.

Doesn't sound like bad pmd at this point.


So there, you've got 2 healthy and reasonable maint. tasks to do. With any
luck, things will start getting better. Good luck.

skk

Hey Mark, Are you stuck somewhere? I have been going crazy for the last 20 minutes trying to figure out why sometimes I see my response in your thread and sometimes see stukreit's reply. Now I realize you started the same threads in 2 forums. If you are not stuck, prepare to have this thread moved/deleted or merged with the other one in the 6.5 forum. Hey, its no big deal, we take all comers in the 6.5 forum and the collective knowledge there will get you fixed up in no time.

As stukreit said, "don't be a hater" these are great trucks/engines once you get them figured out.

Lets all concentrate on the thread in the 6.5 forum, okay?

This does not belong here. Moved to appropriate location..

No codes? Sounds like lots and lots of funky charging issues here. Time for a whole system cleanup on all points electrical. Start with batteries (connections) cables, engine grounds, etc.... No cruise *could* be PMD problem, but you don't seem to have the usual failing issues for PMD. Not to say that it isn't, it's just not the normal routine failure.

Go through diagnostic checklist (click below) for a Q & A session to get intimate with your vehicle.

Thanks for all the good suggestions so far! I'll try each of them in an effort to get my truck back on the road. It's was my daily driver. My truck is not drivable at this time and I have no intention of driving five miles down the road only to have it die again. I'm new to this site and I'm still trying to work out the correct etiquette for posting on the "911" forum. I've had to fire-up a more reliable ride to work, my 1965 Chevrolet Impala station wagon. I still hate my truck :)
Mark
p.s. I love this site!!!!!!!!!!

when you go to release the E brake, while you still have the release pulled, give the E brake pedal a little kick srait up. sometimes, (at least on mine) the pedal will not make it to the top and the daytime running lights wont come on.

I'd start with a new filter and then test for liftpump and OPS operation. A clogged fuel system will do strange things.