Significant gas mileage drop since plenum fix... Why ?
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Thats what im saying.. its been 950 miles now since the intake fix... oil level still hasnt dropped one bit.. Tailpipe is very clean still no more black soot.. Idle sits perfect so i doubt i have a vacuum leak.. Coolant has been staying exactly where i filled it at.. So im not burning a drop a single drop of oil anymore, compression is very good almost too high actually because the engine is gummed up (cylinders are all at 180-188psi) But the mileage just isnt there..
It has gone up since removing the catch can.. Im at 11.6 mpg on the overhead vs barely pushing 9.9 before and for awhile it was at 12mpg.. Im driving it pretty hard too getting it up to 45mph then coasting.. I always found driving it hard from a stop to speed is better on gas then grannying the Jeep to speed.
I also replaced a completetly rotted hose under the Jeep which goes to the evap charcoal canister (smelled like gas and was leaking air) but i dunno if that will help at all. I also drained my oil by a half to 1 full quart.. My friend noticed I kinda overfilled it a little it was sitting above the MAX line so i drained it.. He says that could hurt gas mileage.. I dont see how but ok its drained now. Granted I dont think I'll be getting the 13mpg the EPA estimates because I did put bigger tires on it like 6-7k miles ago and i noticed that lowerd my mpg by about 1 on the freeway and city (before i fixed my intake)
Anyway still not sure what else to do.. I need to get my propane torch out and try using that around my manifold i guess to see if there is any leak... But honestly... if i my manifold was leaking wouldnt my idle be fluctating ?
It has gone up since removing the catch can.. Im at 11.6 mpg on the overhead vs barely pushing 9.9 before and for awhile it was at 12mpg.. Im driving it pretty hard too getting it up to 45mph then coasting.. I always found driving it hard from a stop to speed is better on gas then grannying the Jeep to speed.
I also replaced a completetly rotted hose under the Jeep which goes to the evap charcoal canister (smelled like gas and was leaking air) but i dunno if that will help at all. I also drained my oil by a half to 1 full quart.. My friend noticed I kinda overfilled it a little it was sitting above the MAX line so i drained it.. He says that could hurt gas mileage.. I dont see how but ok its drained now. Granted I dont think I'll be getting the 13mpg the EPA estimates because I did put bigger tires on it like 6-7k miles ago and i noticed that lowerd my mpg by about 1 on the freeway and city (before i fixed my intake)
Anyway still not sure what else to do.. I need to get my propane torch out and try using that around my manifold i guess to see if there is any leak... But honestly... if i my manifold was leaking wouldnt my idle be fluctating ?
Last edited by candymancan; 06-03-2013 at 02:02 PM.
#23
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I'm reeeeeallllyy starting to lean towards a cat. Hell, I get 13 hwy and that's with big tires and I'm pushing more air than you. You said your cat is original? Right?
Mine was starting to clog when before it started rattling. The exhaust guy beating in the pipe just finally killed it.
Mine was starting to clog when before it started rattling. The exhaust guy beating in the pipe just finally killed it.
Im talkin city not highway, highway im getting around 17mpg
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No i havent replaced the o2 sensor or the cat.. I've been waiting on my tax return for it... I just found out my puny tax return was direct deposited into an account i share with my mom and she spent the money... I was told by my tax lady id get a check... Man o man...
Oh well... Thanks guys i guess all i can do is replace my sensor and have my cat looked at and replaced. You guys dont think its a leak from the manifold then right ? Its just weird if it were my cat and O2 sensor why would it do it after the fix..
ALTHOOO i have noticed over the last 2 years my mileage has been dropping slowely.. going from 13.5 mpg easily to 12.5 to 12 then 11.5 i know getting bigger tires didnt help that 4-5 months ago but yea i have noticed its been dropping slowely.. I guess all that OIL burning its been doing probly did mess with my cat an O2..
Any recomendation on a good cat that wont rust out after a year or two ? Same with an O2 sensor that wont cause me codes or anything, because these Jeeps tend to be picky about sensors
Oh well... Thanks guys i guess all i can do is replace my sensor and have my cat looked at and replaced. You guys dont think its a leak from the manifold then right ? Its just weird if it were my cat and O2 sensor why would it do it after the fix..
ALTHOOO i have noticed over the last 2 years my mileage has been dropping slowely.. going from 13.5 mpg easily to 12.5 to 12 then 11.5 i know getting bigger tires didnt help that 4-5 months ago but yea i have noticed its been dropping slowely.. I guess all that OIL burning its been doing probly did mess with my cat an O2..
Any recomendation on a good cat that wont rust out after a year or two ? Same with an O2 sensor that wont cause me codes or anything, because these Jeeps tend to be picky about sensors
Last edited by candymancan; 06-04-2013 at 02:09 PM.
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