bad fuel mileage

[5ton4ever]

I have a 1996 chevy g30 van (ex air force crew van) with a 6.5 diesel. has 90,000 miles on it. It only gets about 11 mpg and is very sluggish when accelerating. It runs smooth and quiet. Any suggestions

 

[WARWAG]

What does the airfilter look like? Brakes dragging?

 

[lavarok]

Turbo or no turbo? Sounds like limp mode. Is it throwing codes?

 

[59797]

getting any black smoke?

 

[5ton4ever]

New air filter. van rolls easily, and I do not drive it hard. I even put taller tires on the rear to decrease engine rpm at highway speed. Maybe a pump/timing issue? I just don't know much about the chevy diesels. And I don't have a code reader, but no check engine light appears.

 

[5ton4ever]

Also, no smoke and no turbo.

 

[lavarok]

Best bet would be to scan for codes. Most parts stores will scan for free.

If no codes, then maybe bad injectors, fuel filter, lift pump, timing, or ? Could be numerous things.

 

[WARWAG]

Usually those rigs sit for a long time in a dirt lot. Field mice find the air intake tube a great place to build a nest. This will cut your fuel eco in half but your engine will run fine. Maybe a bit on the hot side. Pull your entire air intake off and look inside. Bet you have an obstruction of some sort. Good luck. Keep us posted on what it is.