7.5mpg wtf!!!! Help!

[declfier]

Ok i know that jeeps don't really get great MPGs... but i shouldn't be getting 7.5mpg.. i can't figure this out.. she sounds fine.. runs fine.. and it gets about 110 miles to the tank.. this shit isn't right.. any ideas??

[korisu56]

Engine, transmission, gears, tire size, etc. Need a lot more info for us to actually help.

[daddyfitz]

Had a similar problems years ago on a carburetored engine but it was running terribly. No power, couldn't do more than 45 and it sucked down half a tank in two miles. Turns out it was a the pcv valve. Definetly need more info though.

[Jeffb_79]

Looks like you've got a YJ... fuel injected or carb'd? What size tires are you running, what trans and what gearing? Loss of power issues? Bad idle?
Any other symptoms to go along with your bad mpg's?

[declfier]

ok its a 97 tj.. don't know the gears i just bought it..
5spd.. 4.0 fuel injected..
33 12.50 15's

sorry i didn't put that much info up..

i think i might have figured out some of the problem.. when i bought it off this dealership.. they exhaust manifold was cracked and i told them i wouldn't buy it if it wasn't fixed.. so they replaced it with an older model exhaust manifold.. and the sensors that were hooked up are no longer.. so i need to figure out what sensors i need to buy and replace with a new exhaust manifold..

hopefully that'll fix it.. on top of this i'm doing a full tune up within the next week or so.. so we'll see..

Oh and as far as the bad idle.. it idles at whatever RPM it wants.. i think i need to replace the throttle sensor... i dunno.

[korisu56]

Looks like you've got a YJ... fuel injected or carb'd? What size tires are you running, what trans and what gearing? Loss of power issues? Bad idle?
Any other symptoms to go along with your bad mpg's?

Look at the wipers.

[korisu56]

ok its a 97 tj.. don't know the gears i just bought it..
5spd.. 4.0 fuel injected..
33 12.50 15's

sorry i didn't put that much info up..

i think i might have figured out some of the problem.. when i bought it off this dealership.. they exhaust manifold was cracked and i told them i wouldn't buy it if it wasn't fixed.. so they replaced it with an older model exhaust manifold.. and the sensors that were hooked up are no longer.. so i need to figure out what sensors i need to buy and replace with a new exhaust manifold..

hopefully that'll fix it.. on top of this i'm doing a full tune up within the next week or so.. so we'll see..

Oh and as far as the bad idle.. it idles at whatever RPM it wants.. i think i need to replace the throttle sensor... i dunno.

keep us updated.

[declfier]

will do.. thanks guys.

[Jeffb_79]

ok its a 97 tj.. don't know the gears i just bought it..
5spd.. 4.0 fuel injected..
33 12.50 15's

sorry i didn't put that much info up..

i think i might have figured out some of the problem.. when i bought it off this dealership.. they exhaust manifold was cracked and i told them i wouldn't buy it if it wasn't fixed.. so they replaced it with an older model exhaust manifold.. and the sensors that were hooked up are no longer.. so i need to figure out what sensors i need to buy and replace with a new exhaust manifold..

hopefully that'll fix it.. on top of this i'm doing a full tune up within the next week or so.. so we'll see..

Oh and as far as the bad idle.. it idles at whatever RPM it wants.. i think i need to replace the throttle sensor... i dunno.

I'm not sure if things changed between 97 and 05..... I think I have 2 O2 sensors in my exhaust manifold. If those are missing, or not hooked up, that could be your issue.

[declfier]

I'm not sure if things changed between 97 and 05..... I think I have 2 O2 sensors in my exhaust manifold. If those are missing, or not hooked up, that could be your issue.

missing and not hooked up lol.. its like i have an old old exhaust manifold on it.. so i'm gonna have to get the right one for it and find out which sensors i need for it..