real bad gas milage

[JTSRT8]

car is on some heavy 22"

I'm sure that doesn't help.

[doitnow]

are you running larger rims @ tires ? w/out odometer gear change it may be showing 10% less miles on it or more. my son had this on his new tahoe @ got rid of it because of poor mileage. doitnow!!

[oblivion]

Originally Posted by james300c

ok well here the deal...
im only getting avg 10 mpg on the 300c 5.7 auto
im running 180* thermo
cherry bomb cat back
mopar cold air intake
dioblo 93 octane tune

i know this isnt normal...
i recently changed the plugs and wires. car runs greats!
what can i do here??
also car is on some heavy 22" and its a 2005 300c

Depending on what is used in the gas to boost the octane, you may get much worse mileage with high octane gas than with 'normal' gas. In addition to going back to the stock tune to test, I'd try a different brand of gas. Also check the basics--are your tires inflated properly? Is a brake dragging? Did this low-mileage situation just start "out of the blue", or did it correspond with adding the 93-octane tune or adding accessories?

[james300c]

all seems to happen afte the plug change and 93 tune.. i droped to the 91 tune and at 15 mpg now..