I have a 99 ford f350 with the v10 and 180000 miles, stock engine except for K&N filter. Around June it died and I replaced the tps and it worked for a couple months then the same problem came back. I have since replaced the tps, pigtail coming off the tps, cleaned the throttle body and MAF. Currently at the shop but they can not duplicate the problem. Always the same problem, revs up once on its own, cel starts flashing erratically and then it starts running rough. It will usually die within a minute or two after it revs up. The shop thinks it might be a gem module. Any other ideas?

 

GEM shouldn't have anything to do with how the engine runs, nor the CEL light (see my signature for disclaimer)...

Check the voltage at the battery, do the headlights flicker when it's running? Sounds like electrical interference from somewhere, and the alternator having a bad diode (or many) would do drive the PCM nuts.

 

The headlights do not flicker when it happens. All other lights on the dash are solid, no other electrical problems except for a flashing cell. I checked the battery a couple days ago and got 12.5 volts with the truck off. I will retest it and the alternator this weekend.

 

if you have been running your truck and it's 12.5 after you shut it off then you have a battery or alternator problem, battery should read 12.6 after setting over night and 14 or above right after it was shut down. After starting the voltage at the battery should be in the 14.4 range.

Denny

 

I had the battery tested today and it came up as bad and needed replacement. Alternator was good. Replaced it tonight, hopefully it will solve the problem.

 

These new trucks have so much electronics on them and they need a good clean power source, a battery is a great DC filter but if it starts going bad the electronics don't like it. We were with a couple that had a Dodge truck and the transmission was acting up and after a complete rebuild it still was doing the same thing. I turned out to be a bad alternator.

Denny

 

latest update. Truck ran fine with the new battery for less than a month then it started stalling on me again. Exact same problem, truck revs once then stalls out. I have had the battery and alternator tested they came back good, shop said the starter was pulling more amps than it should when starting the truck but that wouldnt cause the truck to stall after it was already running would it?

 

Are there any stored codes?

 

no stored codes. I have ran my reader and the shops reader on it and there is nothing stored. I have also ran it right after it happened before I turned the key off and nothing was there.

 

Latest update. I figured out that something was causing the trucks computer to lose connection whenever the problem happened. I would run a hand held scanner as the truck was stalling or right after with the key still in the on position and the scanner would not be able to communicate the the computer. I pulled the computer out and found it had a SuperChip, on a hunch I pulled the chip out and reinstalled the computer. It has been two weeks since I have removed the chip with no problems or stalling.

 

Nice find

Yeah, I had a SuperChips in my '96 T-bird that would love to get a bad connection and hit a bump, and bang, stall. had to warranty it. Lasted forever after that.

 

I had the identical symptoms and found the identical problem, except added on to mine was the fact the previous owner bent a capacitor over on the board when installing the Jet chip, so I had to replace the whole ECU.

Glad you got it figured out!