Same for most of the cold air intakes.

 

so it got warmer..i was driving home from a buddies after shooting and i broke down.. fuel pump was messed up and stopped working. replaced it and I'm getting 8-9 now. i don't know if its a blown plenum gasket. but it doesn't seem like it. i might run some test and spray starter fluid around and see if it gets pulled in. but thanks for the help fellas

 

That will find vacuum leaks, but won't tell you squat about the plenum leak. Read the plenum sticky and you will understand why.

 

I would suggest you fix everything else on your list before you spend $200+ on a CAI. I went with the K&N FIPK and saw no increase in mileage. My poorly calibrated butt dyno didn't detect any difference in power either. I would go with a K&N drop in filter only.

 

Even if a CAI helps with mileage (mine did not to my knowledge) it would only be like .5mpg. So if a CAI costs $200 it would take a LONG time to pay off. Pull off the throttle body and check your plenum. Takes 10 minutes.

 

CAI doesn't do anything for these trucks. They all draw air from the SAME place the factory system does. Waste of money.

 

Other factors that may contribute to poor mileage are winter fuel and hill terrain if you don't live in flat area. My stock height truck gets 8 to 8.5 mpg around town in the winter due to these conditions. Goes up 1 mpg in summer. If I had larger tires without regearing I imagine it'd be right where yours is.