i have a 95 gmc k2500 6.5 TD vinF with 108k miles. cold air intake and 4 inch straight pipe.
the truck is pretty much 100 percent stock with the original pmd. my concerns are if you hammer on the gas right to the floor, the truck will sputter ilk its not getting fuel, and when i pull a landscaping trailer with a zero turn more and a walk behind, single axle, its almost like it can't take it, blows black and heat climbs, my vortec does a way better job. also when going about 65 -70 on the highway, the check engine light comes on, and runs fine still, but the light will go away when i lift off the gas. then i lay back into it and in 5-10 mins or so it happeneds again. i haven't got a chance to read the code on the highway cause i need a buddy to come with me so i don't end up in a crash. any ideas? i looked around but other similar stories involve the truck stalling, mine has never stalled.

 

It's probably a low boost code. That will make black smoke, low power, and engine temps to climb. Need to hook up a boost gauge and make sure that there is no boost. If there is no boost, it could be bad vacuum pump, boost solenoid, broken vacuum line, or bad turbo. You could tie the waste gate actuator shut, but without a boost gauge I would not leave it or drive it really hard.

 

If you are getting a SES light on the highway it will be there when pull the codes is the truck OBDI or OBDII????

 

the trucks vacuum pump looks like heel, theres a rust hole in the canister and the rubber hose doesn't connect tight anymore, but when the truck at idle, i can't move the waste gate so is is working? and my trucks OBDI, i have a snap on redbrick scanner ill check it with today

 

Well black smoke is normally going to compute to either to much fuel, or not enough air. Since your truck is stock, im going to guess the amount of fuel is correct. So i am also going to go with the vacuum/boost issue.

 

If you have someone else start it and you look at the waste gate, it should move when the truck is started. Still the best way is with a gauge to see the amount of boost. You might be able to read boost on the scanner. I'm not sure if OBD1 shows it or not. But there should be a MAP/boost sensor on your truck, so the scanner should read it.

 

I've checked for codes and there is none what so ever. the highest boost the truck has hit was 3.00 and at idle its 2.17 (according to the scanner, not sure if its lbs) but everything seems to be in check, waste gate moves on start up, and i can't move it while running. only question is, is the boost too low? it may be working, but is it efficient and what is it supposed to push stock?

 

You say the PMD is stock do you mean that it is still on the IP?? if so the symptoms you are describing and no DTC codes sound an awful lot like like the PMD may be failing you should probally consider relocating it to a heat sink outside of the engine compartment alot of people like myself like and use the behind the bumper as a good location here there is not near as much vibration and good cooler air flow which will prolong the life of the PMD

 

truck is out of commission, driving home one day it started sputtering real bad like it does at full throttle, stalled a few times and ran real rough and finally died. there was diesel all over the 2nd to last injector on the driver side, i smelt diesel for a few days but figured it was a fuel return line. i think something happened with the injector or that fuel line, have yet to start ripping into it

 

Does sound like a bad PMD,but also like low boost.
Get a boost and EGT gauge installed asap for diagnosis and engine protection.

Black smoke spikes the EGT';s and can cause a meltdown in short order.

Very likely you are on the money with a leaky fuel return line,injectors can leak at the seam where they are assembled but that is more often a problem with recent rebuilds.