Same here, I ran my truck for about 3 weeks with just the spacer and noticed about a 1 MPG gain. I then installed a air-intake system and noticed a 3 MPG gain. Dosen't sound like much but, after time it'll add up.
Bob07fx2
Originally Posted by bareaneye
I had a very good experience with a throttle body spacer. I placed one on a 97 Yukon and gained about 1-1.5 mpg. When I put a FIPK from K & N on it, I lost!!! The throttle body spacer was the only bolt on that actually performed. I used the helix spiral type.