[wherez_r_u]

I've had my 2004 3.8 since new. Got 80k miles on it now. I have been averaging 22-25 mpg with combo city/hwy driving. In the last month, suddenly my mileage has turned terrible. I now average only 12-16 mpg. Car runs fine--no misfiring, no fuel leaks that I can detect, no vacuum leaks I can visibly see and filters are clean.

I really don't want to pay a mechanic $100+ to diagnose something I can possibly find and fix on my own but I'm not sure where to look next.

Has anyone had similar issues or any ideas where to look next?

Thanks

[Gmezz4]

you might try a fuel system cleaner, at 80k miles your injector lines might be a bit clogged. you just buy it in a bottle and pour it into the tank.

[Must2stang]

I would try and Find Luckas's or somthing like that...Fuel Cleaner Or Get a new Fuel Filter. there Cheap and easy to Install.

[ewells2420]

yeah did you actually look at your filters? or are you just assuming they are clean? Might want to replace the fuel filter and clean/replace the air filter just in case.

[wherez_r_u]

Originally Posted by ewells2420

yeah did you actually look at your filters? or are you just assuming they are clean? Might want to replace the fuel filter and clean/replace the air filter just in case.

All filters are replaced--new filters.

I am trying the seafoam someone recommended and cleaned the MAF with MAF cleaner last night to see how that does.

So far.....

New oil/filter, fuel filter, air filter (all new), seafoam injector cleaner, MAF cleaned.

Will repost results after I burn through this tank of gas.

[64XL500]

See about a locking gas cap. I put one on my 94 Silverado with a 5.3 v-8 and went from 10mpg to 14mpg in town, I also notice that the rice burner across the street from us dosen't seem to get driven as much.

94 V-6 droptop
mike

[crshelton21]

I had this same problem, i was gettin around 24 a gallon and suddenly it just dropped to about 17 a gallon. In my case i noticed one night when i filled up and stopped at sonic on my way home, and there was gas pouring out because i had a bad gasket. You said that there was no leaks with yours... since then i have changed the fuel filter, air filter, spark plugs, spark plug wires, keeping my tires with the proper air pressure, i also had a 2 step fuel system cleaning at walmart done and since ive done all that i am getting around 25 to 26 a gallon, im pleased.

[GRj2k]

im also having this problem i get like 15mpg n i know i have a transmission leak which soon im gonna be fixing. i have a k&n air filter and i clean i just recharged it. about the MAF getting cleaned..my automotive instructor told me that u cant clean it..if u do it will go bad. also where is the fuel filter located at? is it easy to reach?

[wherez_r_u]

Originally Posted by GRj2k

im also having this problem i get like 15mpg n i know i have a transmission leak which soon im gonna be fixing. i have a k&n air filter and i clean i just recharged it. about the MAF getting cleaned..my automotive instructor told me that u cant clean it..if u do it will go bad. also where is the fuel filter located at? is it easy to reach?

The fuel filter is located directly in front of the gas tank. Fairly easy to reach IF you jack up the back of the car. (I'm too fat to shimmy under the back end without a jack). Fuel filter requires a special tool to remove it that I got at O'Reilly's Auto Parts for about $3.50.

[GRj2k]

Originally Posted by wherez_r_u

The fuel filter is located directly in front of the gas tank. Fairly easy to reach IF you jack up the back of the car. (I'm too fat to shimmy under the back end without a jack). Fuel filter requires a special tool to remove it that I got at O'Reilly's Auto Parts for about $3.50.

i put it on a lift today n looked for it..i think i know wat your talking about its between the gas tank n the diferential. its little big i figured something smaller than that. thank you i really appreciate your help.

[wherez_r_u]

Originally Posted by wherez_r_u

All filters are replaced--new filters.

I am trying the seafoam someone recommended and cleaned the MAF with MAF cleaner last night to see how that does.

So far.....

New oil/filter, fuel filter, air filter (all new), seafoam injector cleaner, MAF cleaned.

Will repost results after I burn through this tank of gas.

---------------------------

Well, it helped some. My fuel mileage did pick up a couple of MPG but not nearly what it was before. I'm now getting 18 vs. the 22-25 I used to get before. Not sure what else to do besides replace the MAF sensor, O2 Sensors which the computer says are good.

[Draco_mustang]

HMMM... I have a 2002 v6 auto and I get about 18 in the city or less if I lay on it... so.... you're telling me I should actually be getting way better gas mialage?!

[SirRaven]

Originally Posted by Draco_mustang

HMMM... I have a 2002 v6 auto and I get about 18 in the city or less if I lay on it... so.... you're telling me I should actually be getting way better gas mialage?!

Here I am thinking the same thing. I have an 03 v6 auto and I believe I'm getting around the same 18. I was driving about 53 miles to and from work every day and I would have to fill up every other day. I was filling up at ~ 1/4 tank.

So that's 212 miles between fill ups on almost pure highway driving, normally at speeds of 60-85. Considering I filled up around 1/4 of a tank that means I was getting just under 300miles to a full tank. I have a clean CAI filter but I bet my injectors are dirty.

I need to replace my plugs/wires/clean injectors and filter. Seeing this thread made me realize how bad my mileage has been.

[reds]

plugs and wires really a good tune up...the gas today really sucks this could help