[diecastdude2000]

I have a 2003 dodge ram hemi 2wd with 113k mi on it. 5 spd automatic. I just changed the spark plugs a few hundred miles ago & it helped a little. I am currently getting 15-16 mpg on the fwy on Premium gas, and 13-14 on regular gas. 12-13 mpg in the city on premium & 10-11 city on regular. I have tried "fuel system cleaner" additives in the gas tank with no improvement. I am not sure what to do. I know Hemi's aren't good on gas but as far as I've read I should be getting better than what I am now, and at the very LEAST able to run 89 octane instead of 91. Please help me!

 

[Pmann]

so the truck is stock pretty much? those numbers aren't too far off what I used to get but now I get at least 18 on the highway but I have intake and exhaust mods. I use 93 octane though but I don't have a tuner. Personally I've never seen any improvements from using the fuel system additives.. Maybe try checking the tire pressure

 

[Raneman]

I have a 2003 dodge ram hemi 2wd with 113k mi on it. 5 spd automatic. I just changed the spark plugs a few hundred miles ago & it helped a little. I am currently getting 15-16 mpg on the fwy on Premium gas, and 13-14 on regular gas. 12-13 mpg in the city on premium & 10-11 city on regular. I have tried "fuel system cleaner" additives in the gas tank with no improvement. I am not sure what to do. I know Hemi's aren't good on gas but as far as I've read I should be getting better than what I am now, and at the very LEAST able to run 89 octane instead of 91. Please help me!

For one, do NOT run regular gas in your truck unless you have a tuner that tunes your truck so you can run it. Hemis are supposed to run 89, running the regular will cause you engine to knock. And also, without a tuner, running higher octane gas then 89 in it can actually decrease your power.