MPG probs

dawm · Post by **dawm** » Fri Jan 07, 2005 5:54 pm

i average 16mpg, any clues why? no codes, no sensor mods to my knowledge, i drive about 5 miles, with 6~ stop signs/stop lights on my way work (one way). anyone got a clue as to why i get such shitty milage? i only use mobil gas, and 87 octane. shortblock was replaced back in october as well as the cat and i believe the o2's. other then a K&N filter in the airbox the engine is stock. (2002 R/T)

Polish_neon2 · Post by **Polish_neon2** » Fri Jan 07, 2005 8:43 pm

i might be wrong, but im pretty sure that your supposed to be running 91 octane, that may have a bit to do with it, but not that much,

dawm · Post by **dawm** » Fri Jan 07, 2005 9:02 pm

incorrect, it performs best on 91+ octane, but not required. as did the 1g DOHC (unless you had a mopar pcm then you were required to run 92+ octane, or you would get knocking) previous owner used 87 octane and was achieving 30mpg

evlneon · Post by **evlneon** » Fri Jan 07, 2005 9:27 pm

the only reason i can come up with is that you're a little heavy on the throttle between those 6 stop signs. and anywhere in general i suppose.

dawm · Post by **dawm** » Fri Jan 07, 2005 9:53 pm

evlneon wrote:the only reason i can come up with is that you're a little heavy on the throttle between those 6 stop signs. and anywhere in general i suppose.

maybe, but the roads are complete shit here and being i have about 4" clearance and stiff springs im not driving all that aggressive.

Brett R/T · Post by **Brett R/T** » Fri Jan 07, 2005 11:49 pm

87 octane will give you crappy fuel economy as well as performance. I've tried it and so have others here.

the other reason is probably because your short trips aren't letting the engine warm up fully so it's not operating as efficiently as it would if you took 15 mile+ trips. I have the same issue living in a city.

03rtneon · Post by **03rtneon** » Sat Jan 08, 2005 2:34 pm

my r/t hates anything less than 93. i ran 87 in it one time and never again. ran like ass.

DvsKreationz03 · Post by **DvsKreationz03** » Sat Jan 08, 2005 4:51 pm

my sxt is the same way, it hates whenever I put low-test in it. Livin in T has it's advantages, like 93 octane for example. CO sucks though, cuz the most I can get is 91, and altitude is a killer.....

01NeonRT · Post by **01NeonRT** » Sat Jan 08, 2005 7:13 pm

My car runs the same on 87, but doesn't get as good of mileage.

TomZ · Post by **TomZ** » Sat Jan 08, 2005 10:43 pm

Most likely, your short drive is killing your MPG. The emissions system stays in "open loop" mode until warmed up, then goes into "closed loop" mode after that. Your PCM will command a rich condition until closed loop. Is your long trip/highway MPG OK?