1995 6.5TD skipping at high rpm

[yz837]

I just got the truck and like it alot, but im not seeing the expected fuel mileage, and it seems to skip if you lay into the throttle, but fine a low rpm. Any ideas?

[Robyn]

More info please.

Mileage on these can vary a lot. My 3500 Dually 4x4 will get 19 hwy running light.

If yours is stock the Cat could be plugged.

This "skipping" only at high speed (RPM) ??
Any corelation to the fuel tank being full or near empty.

The filter harness on the optical sensor can cause a fish bite sort of thing.

Air leaking into the system will drive it nuts.

If the issue only happens with the tank at or below 1/4 could be a leaking bypass valve in the suction tube in the tank.

Oil pressure switch could be failing or has failed and causing a shortage of fuel pressure and volume to the IP.

****>filter is always the first thing to check<**** The little dixie cup filters are not near large enough and can plug easily if a bad load of fuel has been pumped on board..

Water can wreck an IP quickly.

Open the drain cock at the front top of the engine by the upper radiator hose. the drain line should allow fuel to flow freely with the engine idling.
If no fuel comes out or the engine dies then you have a lift pump issue.

Either the pump or the Oil pressure switch could be to blame.

If these things check out and still no go then add a piece of clear plastic tube to the return fuel line coming from the IP (little one) and run it up by the wiper and loop it around and back to the return.

If you see a stream of bubbles this would mean air is entering the system and will wreak havoc with how the engine runs

Best
Robyn

[MrDiesel]

Mine used to skip when I really mashed the throttle, I thought it might be the tranny going but it turned out to be the early signs of my lift pump failing. It just couldn't keep up with the fuel the engine needed when I had to the floor. Changed the lift pump and it hasnt done it since.

[yz837]

Its got 130k on the truck and about 900 miles on the motor. It starts to skip and buck when I lay on it even at low speeds. I think the poor fuel issue is because the motor is breaking in, but thats all.