That's odd, huh. Is it plausible that my mileage would be -worse- after the TB cleaning?

 

how long (miles) has it been that you are basing your mpg claim on?

and its possible sure, if the carbon build up was minimal but smooth, and then you cleaned it and its rougher surface now, sure its plausible that the air is not flowing as smoothly.

but i think its going to be more of a weather/driving habit change that you noticed your mpg drop from.
-Patrick

 

A dirty TB will not hurt gas mileage. Unless it is completely stopped up. So, if you truly have a mileage decrease, something else is wrong. Cause cleaning it shouldn't hurt anything.

 

If the precleaning mpg numbers are older than a few months the numbers will be skewed as you may be running crappy winter gas and not the summer mix.