6.5 TD skips along intermittently

[trea007]

Have a 94 6.5TD 3/4 ton Suburban and its been great til recently. Has 205000 miles on it. Recently it was hard to start when it was cold or hot intermittently and would "miss" as you're driving. Had the Fuel driver replaced and now it starts great but the "miss" is still there intermittently. Sometimes it'll miss just driving at a constant speed other times under acceleration sometimes not at all. I do notice that when I start it in the morning it runs a little rough with black smoke for about a minute or until you step on the pedal once or twice. Had the fuel pump replaced, injectors tested, oil switch tested and the lift pump tested - all were Ok Any ideas? Terry 602 373 2530

[john8662]

Hey Terry,

This sounds like an air in the fuel system issue. Do you smell a whif of diesel fuel when you pop the hood, or does the smell of fuel kinda linger underneath the hood?

If so, you may have a leak in the all-so-common fuel filter housing, they're prone to leaking.

You may consider installing a small piece of clear hose on the fuel outlet on the injection pump (top of the pump) to observe if you are getting any air running though the system when the engine starts and is running, or when it's running poorly.

If you find air bubbles when it's running or immediatly when it starts (have someone start it for you cold and observe), then you'll need to look for sources of the leak.

Welcome to the PaGe!

J

[1994-chevy]

I also have an occasional miss when sitting none at idle. I also have a shuttering on the highway. Acceleration is great and no air in the lines. Been messing with this for a couple of months. Nothing seems to help.

[Robyn]

Sounds like an injector issue.

I flakey injector/s can cause goofy misfires

Any SES LIGHT CODES

Another possibility is the filter harness on the IP (Has a rectangular box in the harness and plugs into the optic sensor on the top rear)

A failed filter can cause "fishbite"