horrible gas milage

spyder041 · 03-07-2008, 09:29 PM

been getting progressively worse mpg on my truck..1/2 tank is at 115 miles.. Did a tune up and it didnt make a difference.. Can my truck just need to be tuned or something? Only thing I have done is borla cat- back and an open air cone.. Drive like a grandma too..

humanoid · 03-07-2008, 09:34 PM

Are you getting any codes? Maybe the MAF sensor is dirty too.

Firdaddy · 03-07-2008, 09:35 PM

i'm right there with ya man, nothign i do makes a difference

spyder041 · 03-07-2008, 09:37 PM

Quote:

Originally Posted by humanoid

Are you getting any codes? Maybe the MAF sensor is dirty too.

No Codes.. When I did my tune up I cleaned the maf also.. Wonder if I put my airbox back in if it would help? Maybe do thedeckplate.. I used to get 250 miles when I had my truck stock

dropthattaco · 03-08-2008, 12:32 AM

Might try replacing your front o2 sensor or sensors (the one or ones before the cat). They can get sloppy and not set a code sometimes. Also, does your truck warm up to normal operating temp?

Rembrant · 03-08-2008, 03:46 AM

Have you tried a good does of Seafoam or similar product? Could the cat be gettin' plugged up?

I'd at least try sticking some of the stock bits back on at least to rule them out....
I had the exact same truck, right down to the Ivans and same size tires, and I rarely ever got below 300 miles to a tank before the fuel light came on....even got as high as 310-315 on the highway b4 the light came on.

In any case, good luck...hope you get it sorted out....gas is spendy these days.

glassdoc · 03-08-2008, 07:03 AM

Where do you buy your fuel from? Check the ethanol sticker on the pump.. The more ethanol, the less miles per gallon you are going to get. Clean the MAF, if it is a sensor its likely the rear O2 sensor, 60k is recommended change from Toyota. Overall how does it run? Idle good, throttle response? Have you looked at your plugs? Pull one and check the gap, they do change on the 3.4's after having been run for a time. You mentioned the cone filter. Did you oil it up? Maybe it coated the MAF, maybe it has too much oil on it and not letting in enough air..

Quote:

Originally Posted by spyder041

been getting progressively worse mpg on my truck..1/2 tank is at 115 miles.. Did a tune up and it didnt make a difference.. Can my truck just need to be tuned or something? Only thing I have done is borla cat- back and an open air cone.. Drive like a grandma too..

pug407 · 03-08-2008, 09:50 AM

What exactly you call a tune up, what parts you changed, cleaned...?

chipsndukes · 03-08-2008, 07:23 PM

Quote:

Originally Posted by dropthattaco

Might try replacing your front o2 sensor or sensors (the one or ones before the cat). They can get sloppy and not set a code sometimes. Also, does your truck warm up to normal operating temp?

happened to me on my truck mileage went from 25-26 to 21-22 after did some engine work (head gasket), the front O2 sensor flaked out but didn't throw a code, switched it and went back to 25-26 instantly, what drophat says above is true, don't have to have a code to have a bad sensor, would go with this solution.

CD

Tacasandburritos · 03-10-2008, 12:15 PM

Make sure your gas station gets alot of traffic. I had MPG issues as well by going to po-dunk gas stations that saw maybe one car a day. The gas just sits in the tanks and pretty much turns into water.