Is there any sure fire way to tell if the glow plugs are bad or if the injectors need to be replaced. I had hard starting last winter and also lost 2 mpg that has not come back. Tried replacing the fuel filter - did not help.

This is on an 02 Chev. Any help would be greatly appreciated.

M

Did you put bigger tires on it?

Bad Injectors:

Diesel In crankcase
Loss of power
Excessive blue/black smoke (unless you have a tuner)
Considerable Mileage

Glow Plugs
White smoke?
not really sure otherwise, duramaxes dont ussually burn up glow plugs, they are designed to last for 200,000miles

I did put new tires on it. Mich LTX mud and snow 10 ply same size. Thought this may be the reason, but can't confirm it. Same tread pattern as the oem firestones but more sipping.

Seems to have lost some power, but don't see any smoke unless it down shifts coming out of a valley. No evidence of fuel in the crankcase

???

m

If there the same size and load range you probably shouldnt have lost any mileage. If its loosing power and mileage, it could be injectors. If you have a flash tuner you could use it to check the balance rates.

Its up to you, id try taking it to the dealer, you do have the 200k warranty right? I think youll have to pay a 100$ deductable, if it seems bad enough to you Id take it in.