Just tried again today and was 17.1 with %50 highway and calculating came out 1 mps under what dash readout said. I can reset the trip on the ceiling when hitting the highway and get close to 25mpg but as soon as I hit town for even a short distance it dies off.

 

That's normal.

 

did better before the tuneup.

 

Are the plugs you used OEM equivalents?

 

Have you read the temperature with a scan tool to verify it is running up to proper temp?

 

We put the basic Bosch in our '03 SXT w/ the 3.3 and the thing never got past 15mpg. I changed the NGKs that were original to the van w/ 93k on it back in '13 and since then We've put over 60k on it. This last week I put the Autolite Iridium XPs and it's pushing just around 415-430/tank for mostly city/mountain roads.

 

Just drove 71 miles all in town and readout said 13.3mpg. Filled it up and calculation said over 19mpg.
Guess will really see when I put a couple thousand on it over the next week while on vacation.