i have looked at a few things, and i cant seem to figure out why its getting worse i only have 44K miles.

any common ideas?

 

have you put an oiled air filter on it?

 

no way those things are bad, i heard GM is going to start voiding warranties cause the oil jacks up the MAF.

 

its all this crappy gas there selling us with 10% ethanol

 

I've ran several different oil type air filters on pretty much all my vehicals with no problems at all. Both my Tahoe and my Silvy have the K&N CAI on them and both trucks get great gas mileage. I've ran the one on my Tahoe for over a year and ahalf.

I do agree the new dry filters are better, but it's all how you oil the filter. I've seen several peoples filters who prolly used the whole can of oil at one time!!!! And they wondered why they always had a reddish purple puddle under the air box area on the driveway!!!!!

 

Ethanol mixed fuels do get slightly less gas mileage compared to what we use to run.....

 

Have you cleaned the injectors at all? The fuel isn't as clean as it could be. I'd recomend some Seafoam or some Lucas oils fuel additive to clean the injectors. I usually double the amount they suggest. The biggest increase I've noticed is when the dealership took out the injectors and put them in some sonic washer thingy. Crazy good gas milage after that. But the bad part is it costs a lot to do and it gets gummed up again in 3-4 tanks of gas.
I like the economy after I get done running cleaner through the tank of gas. But the poopy part is the money saved from the increased economy usually is almost enough to pay for the additive you put in. So it's a push either way, same money. I do it anyway, it makes me feel like I'm doing my part to save the enviro

 

keep the right foot out of it!!!!

haha

no really i have found in my 496ci that running at 55-60 mph i get 15 mpg!!! this is no bullshit...

 

maybe change the fuel filter and make sure its got a good air filter in there.
i change my fuel filter about ever 25k miles.
i knock down 22mpg

 

Two cans of seafoam in the tank with 91+ octane then change the fuel filter after you run the tank out, and don't fill up or top off the tank till the light comes on.