2003 Chevy Truck Poor Performance and fuel mileage

Tiny
ROB HAUBOLD
  • MEMBER
  • 2003 CHEVROLET TRUCK
  • V8
  • 4WD
  • AUTOMATIC
  • 73,000 MILES
My 2003 Chevy 1500HD has a 6.0L in it that feels like it's "pulling hard" all the time. At 60mph it may need to downshift just to climb a hill. Pulling my boat this all gets much worse. Fuel mileage is down, around 6mpg in town and 10mpg highway. Also with cold morning starts I will sometimes get multi-cylinder misfire codes. No body seems to have any idea why including the dealer. They did the recomended throttle body cleaning and sent me on my way. I would be greatful for any advice.
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Tuesday, January 13th, 2009 AT 9:05 PM

1 Reply

Tiny
GFIMOTORCARS
  • EXPERT
I would definately recommend a tune up. With GM vehicles I have worked on with issues of poor performance and fuel mileage occur usually around 60k. If this is your case a couple hundred bucks in parts and a Saturday may get some much needed kick back in your truck. Start with a new fuel filter and a set of spark plugs and wires. Also get some fuel injector cleaner and send it through the tank. This is also a great time to check your belts and fluid levels. When you change the the plugs note any severe wear on the ends of the spark plug. Here are a few pics to help with spark plug diagnosis. Keep in mind abnormal spark plug wear can cause interesting issues with misfiring, even intermitent one's.


http://www.2carpros.com/forum/automotive_pictures/294900_normal_1.gif


Normal


http://www.2carpros.com/forum/automotive_pictures/294900_oil_1.gif


Oil Fouled


http://www.2carpros.com/forum/automotive_pictures/294900_overheat_2.gif


Overheated


http://www.2carpros.com/forum/automotive_pictures/294900_spworn_1.gif


Excessive Wear


http://www.2carpros.com/forum/automotive_pictures/294900_ash_1.gif


Ash Deposits


http://www.2carpros.com/forum/automotive_pictures/294900_carbon_1.gif


Carbon Fouled


http://www.2carpros.com/forum/automotive_pictures/294900_detonation_1.gif


Detonation


http://www.2carpros.com/forum/automotive_pictures/294900_fuel_1.gif


Fuel Additives
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Tuesday, January 13th, 2009 AT 11:36 PM

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