Questionable Mpgs Silverado

[jonoman69]

Hi, I know this is a stupid question for we are talking about a 4x4 v8 truck. But, in the last little bit ive notice my truck to be getting rather worse gas mileage then before. I just bought it about 3 months ago, its a 2004 single cab long bed, 4x4 silverado with the 5.3. Im getting close to 20L/100KM. Which im not sure is so normal. The truck only has 74000km on it. Atleast half probably more of my driving is done at a steady 80km/h. The main reason i bring this question up is because my cat converter just had to be replaced, it basically fell apart inside. I asked the tech what could cause this and he told me one thing is if you notice worse gas mileage then normal that can cause it. Any help would be great, im just looking for an opinion before i take it into the dealer, i only have a couple thousand left on my used car warrenty.

 

Thanks Jon

[spartus]

Hi, I know this is a stupid question for we are talking about a 4x4 v8 truck. But, in the last little bit ive notice my truck to be getting rather worse gas mileage then before. I just bought it about 3 months ago, its a 2004 single cab long bed, 4x4 silverado with the 5.3. Im getting close to 20L/100KM. Which im not sure is so normal. The truck only has 74000km on it. Atleast half probably more of my driving is done at a steady 80km/h. The main reason i bring this question up is because my cat converter just had to be replaced, it basically fell apart inside. I asked the tech what could cause this and he told me one thing is if you notice worse gas mileage then normal that can cause it. Any help would be great, im just looking for an opinion before i take it into the dealer, i only have a couple thousand left on my used car warrenty.

 

Thanks Jon

 

Try these:

 

Tuneup

Fuel filter

PCV valve

Tire pressure

Have fuel injectors cleaned with a kit that hooks up to the fuel rails.

 

 

This past summer I cleaned the injectors on three vehicles, all of which had around 100k on the odometer. They all picked up 1-3 mpg on the highway.

 

Also, we are now on WINTER BLEND fuel, so you may get worse mileage from that too, depending on your area.

[1999 Tahoe 4x4]

It could be of course many things. BTW: You did not note if 20l/100km is in city of freeway type driving. Check your air filter and one of the things I would keep an eye on is the thermostat too. Some people put lower temperature thermostats in or take the thermostat out. If you are driving without thermostat your cat is likely to fail prematurely.

[pwall]

20l/100km doesn't sound that unreasonable, especially if that is mixed city-highway.

For daily driving, I'm getting around the same.

 

Hmmm...should I be getting better ?

[Truckin2003]

my truck and my girlfriends car are also getting worse gas millage this winter. The only thing i can figure is the fuel or something. Maybe they are mixing an additive into it for cold weather or something. My truck has dropped about a 100 mile to a tank of gas and my girlfriends car has dropped 100-150 mile to a tank of gas.

 

It Sucks!!!