okay so i have a 99 max with no engine mods but a cai.....the problem is im getting 10-13 miles to the gallon....i have no CELs and i also had the obd2 scanner checked and nothing came up....i have 17 in cabo rims maybe thats why? well i bought a new KS but i wanted to know if its worth putting in? if theres no codes can that still be the problem.. any help on fixing this problem would be greatly appricated. by the way it is an auto

 

IIRC KS sometimes doesnt showup......im not sure.Lets wait.

 

Are the tires inflated properly? Could also be the knock sensor, though.

 

u have a hole in your fuel tank....

 

Change the upstream O2 sensors.

 

if you already bought a new KS why not put it in and see if that makes a difference

 

Yes. you should change you KS and see if there is a difference. You should check your air filter too. When I got my car - 98 GXE auto I got really bad gas mileage. Then I did some maintenance like new KS, good air filter, fuel filter etc and now way better!

 

yea fuel filter is my first suggestion if you are getting no KS codes.

but also you should just do a general maintenance-overhaul on your car; clean the TB, IACV, replace air filter etc.

if there was something seriously wrong like dead 02 sensors, or a knock sensor, your car would be throwing a code.


btw, you are actually getting your codes read right and not just assuming that because the CEL isnt on, there arent any codes?

go to autozone/advanced auto and have them scan your ECU for free

 

might as well change the spark plugs while you are at it

 

yes this is another good suggestion that would not be tripping your CEL

 

okay i went to autozone no codes..... ill change my oil. oil filter. ks. spark plugs.air filter. check my inflation. and how do i clean my TB, IACV?

 

oh yea could my brakes be stuck i heard that in a past thread?

 

it would probably make noise, like a soft grinding noise, if they were

plus your rotors would be smoking at the end of a long drive.

 

search

there are a plethora of writeups

both are pretty straight forward. just disconnect hoses/plugs and unscrew the bolts and you are all set.

 

You are probably calculating your MPG's wrong if you're getting such low numbers. Many things are probably in need of cleaning/replacing and you might want to consider doing a tune up to get your car to spec...

 

My guess would be your 02 sensors and a good healthy tune up

 

im pretty smart with math.. =] and i pretty much can watch my gas meter drop as i drive. im gonna work on those things thanks very much