I just bought a 2001 GMC Sierra 2500HD Crew Cab Duramax. Right after I bought it the check engine light came on. The dealer said they had to replace the fuel regulator sensor kit. Now Im only getting about 12 - 13mpg. Also a friend of mine thinks it has a performance chip. HELP!! Thanks!!:ro)

Why does he think it has a performance chip? Look under the hood on the drivers side. You will see 2 big plugs on the side of the engine. Is anything plugged into them?

These duramax's are pretty snappy. If he is used to older Cummins or Powerstrokes or 6.5's the Duramax will feel a lot faster.

As for the fuel mileage, you might want to ask your dealer about that. It could be injector related.

What cab and box configurations is the truck and is it SRW or DRW? Also is it 4x4? Are those fuel mileage readings from around town or on the highway or towing or? As you can see more info is necessary.

I assume you got better mileage before the Fuel pressure regulator was changed?

That is around town, it is a crew cab. I dont know if it got better fuel milage before the fuel regulator was replaced because it was replaced 2 day after i bought it. I just called GM and they ran a vin check and all 8 injectors were replaced 5/04.:grd: J.L.