so, a ported throttle body was the "fix" but you never found out what caused the drop in mpg? typical mechanic - just keep throwing parts at it until something works. isn't that what the "stealership" does?

ha!ha! just having some fun with you. i asume you had the pcm re-tuned after replacing the throttle body - any chance the original programming could have gone corrupt and this was the problem the whole time?

 

Good to hear a review on the ported throttle body. That is my next mod. I've been tying to get in contact with him by E-mail. Can't wait!

 

That is what I thought at first, that somehow the computer went back to stock settings, who knows. I thought about trying another PCMtune and seeing if that makes a difference, but your right. I have thrown enough money at it for now.. I am just gonna drive it, and see how she runs for a few months. I will add the Ported TB is makes it much more fun to dirve

 

this thread caught my eye because i noticed that i was filling up more than usual lately. i hadn't calculated mpg in a while but i went from averaging 16 - 16.8 mpg (depending on how much hiway driving i did) down to 13.3. most of the loss i attributed to bigger heavier tires that i recently had installed. i checked tire pressure and the installer had 35 psi so i upped to 42 and mileage improved noticeably. i then replaced the spark plugs and saw yet another mpg increase, not to mention restored power and acceleration. i filled up yesterday and when i was doing my math i realized that i had not been factoring in the additional circumference of the new treads. with that equated i came up with 14.9 mpg, which i can live with, although i would like better mpg's.

thanks for keeping us updated on your progress.

 

If you have a Shell station near you it might be worth a try to see if you get another mpg. I have been testing the major gas brands over the last 3 months or so and hands down my H3 runs better and I always get .5-1.0 mpg increase over the other top tier gas in our area.

This winter has been really good for this unscientific test because the temps and weather have been so consistent. I run at least 3 tanks of each gas and average those. My weekly driving habits are very routine so I feel like I can get fairly consistent comparisons among the choices. Aside from the mpg increase, I also have basically no vibration at idle and better throttle response. Most of the winter blends at other stations make the vehicle shake like crazy. The easiest way I can explain the difference in the throttle response is its like the difference between winter and summer blends. Winter blends make the vehicle seem very sluggish imo and usually I can tell almost immediately when the switch is made in the fall and spring.

Anyway, its worth a shot. Like I said, it is not a scientific study, but I can definitely tell a difference.

 

My mpg has also dropped without any change or mods. Today i got a CEL. Codes P0171 and P1174. Says something about MAF sensor and Clogged Injectors. I am going to try some injector cleaner and a full tank of gas and check the MAF for dirtiness. Any other suggetions?

 

does anyone know of a GOOD fuel injector cleaning additive?

 

Techron fuel system cleaner - 20oz treats 20gal. It is the same additive that the Top Tier 1 fuel stations use in their premium fuels. You can get it at almost any autoparts store. I usually pick up 2 or 3 when they are on sale!

I use a bottle 1 tank before every oil change.