I've got a 94 turbo 6.5l vin S that "missfires" or "sputters" at high rpm. It will do this when in park while reving it up or while driving, it occasionally will have white smoke at high rpms. It does have a bit of a hard/long start as well despite just installing new ac delco 60g plugs and a solenoid to override the relay.

From what I've read online this is commonly related to a LP problem, but I get fuel out of the tap at the fuel filter though, and consistently get current to a test light at the LP connector so I'm a little puzzled. Is there a possibility that the oil pressure sensor is flaky and is not accurately powering the LP at high rpms? Or do I have an injector/injection pump problem? (truck has 198,000 miles and have no knowledge of prior maintenance so I plan on replacing all injectors, just waiting on bonus check) I'm trying to get a video uploaded, any help is appreciated

 

For some reason this weekend when I came out of the store and went to pull out of the parking lot I pressed on the accelorator and it was like it wanted to go but something was wrong, it wouldn't go over 1,200 rpms or so much less build any boost, pulled off the road and held the accelorator to the floor and it revved up and ran fine again?

As well I installed a fuel pressure gauge, I get about 5-7 psi at idle. I also have injectors on the way. Hope this fixes it? Hate not being able to reliably drive the truck

 

Check the last ditch filter on the fuel heater mast in the filter manger as well as the sreens in the IP inlet fitting.
Also replace the IP fuel return line with clear diesel rated line and watch for bubbles,bubbles indicates air intrusion pre LP.

Another cause for fishbiting is a faulty OS electronic noise filter,remove the filter harness and get enough ferrite core from radio shack to cover all the OS harness wires.
http://www.radioshack.com/product/in...ductId=2103222

 

Sorry for not following up sooner, I work full time and to go to college full time so I haven't had a lot of time to mess with the truck. I will say since posting I did put in a new set of injectors and OPS and was about to sell the truck until tonight due to it running so terrible and throwing codes(17,18,29,35,36,48,62,78,85). I noticed when I went to drive the truck this last weekend to keep it from setting too long that if I really got in the pedal the transmission would hesitate to shift and the engine would sputter and then shift hard once you eased off the accelorater. I did some searching online and read something about there being a noise filter to the injection pump which would go bad and cause these exact same symptoms, so tonight after replacing the OS for kicks and giggles and having no improvement I took the intake off so I could get to the IP easier and removed the noise filter...As soon as I started the truck with the noise filter removed I knew that was it. Fires right up now and hauls!

Absolutely happy I bought the truck now, best $500 I ever spent.