rough idle & throttle sticking in park

[dbxtr3]

One of the company trucks I maintan at work is a 95 Chevy 3500 6.5TD 16' stake bed truck 2wd.

It get's very little use we have put only around 25000 miles on it in 5 years. But this thing a has had a TON of problems since we bought it. It has had a new PMD, glow plugs, (2) injector pumps, lift pump, air pump, transmisson, A/C compressor, wastegate solenoid, and more.

Well today I started it and it just rev up to 4000 rpm and died then I started it again and it idle about 2000 rpm then started to jump from 800 rpm to 1500 rpm. If you touch the gas pedal it will rev very high then almost die. It is pouring out black smoke. The truck has 155,000 miles on it don't know if it has ever had injectors put in it. But the truck ran good last time we had it out which was about a week ago. Matter a fact it was running the best it ever has (turbo spooling loud and everything). I limped the truck around the parking lot it was a 30 degree out Friday when it first did it and put it in the heated garage. It is about 65 degrees in the garage today and it is doing the same thing. What could it be? injectors? TPS?

The truck starts up with ease I can hear the lift pump and glow plug relay working. Their is no check engine light on but the glow plug light is flashing a few times when idling when you first start it up. But it has been doing that for a year or two.

If you touch the gas pedal the motor will rev up and stay reved up until you turn the key off. I only does this in park though. If I start the truck put it in drive and give it gas it drives like a normal truck.

[Sundance]

Rookie here but..................

"Their is no check engine light on but the glow plug light is flashing a few times when idling when you first start it up. But it has been doing that for a year or two."

My understanding that the PMD is the first thing to look to if there is no check engine light. Where is the PMD mounted????

I am fairly sure that the glow plugs often cycles a couple times after start up in cold weather. Both mine do......

[dbxtr3]

The pmd is mounted in the stock location. But is only 2 years only and has less than 10,000 miles on it.

[Oldsmoke]

The first thing I do when mysterious things start to happen is take my truck to a local diesel mechanic I know who is familiar with the 6.5TD and get him to hook it up to his scanner. He has always been able to tell me where the trouble is and how to fix it. Has saved me a lot of money.:)

[Sundance]

Oldsmoke has a good suggestion for sure.

Being the PMD is mounted in the old position if it isn't a problem now it will be a problem. Get it out of that hot spot.

Get a used, tested, PMD or a new one and swap it. You can just plug it in and wire it to the intake (grounded of course). If it solves the problem them get a cooler and move it to a cooler location. If it doesn't solve it, put it in the glove box......... You'll need it eventually if it stays in the stock location.

[torque454]

I would say there is something wrong with the TPS OR the fuel solenoid. If the engine revs on its own that is often an injector pump problem or TPS. Where are you getting those injector pumps at? If you went thru two of them that quick, maybe it shelled another one. In that case id go to a different supplier for a pump this time. Also the way i understand it, not every shop puts a new fuel solenoid or crank sensor on new IP's so it could easily be the fuel solenoid if thats the case.

[grancito]

Put some additive in the fuel, the pump has damp fuel in it and is sticking.