HORRIBLE MPG????

[02_chevy]

Whats up guys,

Long story short my truck has recently been getting the worst gas mileage ive had since i owned it. Now i expect to lose MPG from bigger wheels and no bumper, etc but i took a trip to AC over the weekend and i got 11mpg on the highway doing about 75 at 2000 rpm. I did just add a roof rack and figured it would add some drag but i used to get 15-17 mpg on the highway. Could the rack really have taken that much away??

Also My power steering is leaking a lot and not sure from where, the cooler is new and the clamps are tight but a good amount is leaking. Are there any places that are known to leak in the power steering system?

Thanks guy! Love this site!!

[Trail X]

11 mpg seems a tad low for your circumstance, but not insanely low.

What gears do you have and what size tires?

[HARDTRAILZ]

Honestly... I would not give a shit about one trip and the MPG. Too many variables to really know where you stand. Average a few tanks and see how it is. You coulda had some crosswind or headwinds or tires at different PSI cause of temp changes, maybe a crappy batch of fuel in it. I have had tanks that average 12-13 and others that push near 20. Neither is truthful or tells me anything. My long term averaging has me between 15 and 16 in all sorts of driving. I do watch the instant and avg on the Scangauge to see where the sweet spots are and do not use cruise control at all.

I have been dumping PS fluid for a bit and am pretty sure it the seal going into the rack from the steering shaft. I have the seal,but have not had time to replace it. I just buy a gallon of PS fluid every couple months and fill it up when it whines.

[02_chevy]

im running 33's with 3.73s.

I have taken the truck on a few trips actually but this was the first one i did the avg gas mileage just to see. I did notice in the past month that the overall mileage of one tank has dropped a lot. i used to get 220-230 out of a tank, now im lucky to reach 200

Theres no harm in just refilling the pump is there?

[HARDTRAILZ]

So you have the lil tank and lost about 2 mpg. Not so bad for all your mods.

It has worked ok for me for most of this year. I am sure it is not the best for it, but I will just change the pump if it dies at this point.

[ErikSS]

Your mileage seems low to me. Kyle was right, track several tanks and average it before you waste much time or money on it. For the record, I'm usually 13+ with my LS2 and 35s.
You can just add power steering fluid. If it got too low, you can turn the tires lock to lock to push air out of the system and recheck the fluid level.

[02_chevy]

on the highway i lost about 5-6 mpg, around town i expect shitty mileage. ill prob just throw some fuel system cleaner in a suck it up but just wanted to see if there was a reoccurring thing with these trucks

[ErikSS]

When did you loose the MPG? From bone stock til now?

[02_chevy]

Honestly just noticed it after the roof rack, It dropped from doing the lift and wheels but thats expected

[ErikSS]

I don't even have the factory roof rack. I have heard complaints that aftermarket roof racks really affect our MPG. I know some guys modify or remove them because of the drag.

[HARDTRAILZ]

on the highway i lost about 5-6 mpg,

How do you know this? You did once that you report, but it could have been a fluke.

I lose about 1-1.5 mpg with the basket on top. It has been less with the deflector down to roof and the lightbar filling most of front area of basket.


EDIT-- Not sure when you lost the front bumper but that is a major hit on aerodynamics as well and will hurt the mpg.

[02_chevy]

Sorry i should have explained better, That one trip constisted of too and from atlantic city then to and from staten island, then the following day was another tank. all in all i filled up 3 times in two days and did avg mpgs on those three tanks. The bumper one the other hand has been off for a while now but i plan on putting it back on.

Sorry for the lack of info its 10am and already been a long day

[HARDTRAILZ]

fair enough.

[02_chevy]

You think the roof rack could have really killed the mileage that much? Its a Curt roof rack BTW

[ErikSS]

I can't see 5-6mpg.

[HARDTRAILZ]

Nope. I did not lose that much with a basket and tire up top.

[Trail X]

Dan, what's your gear ratio and tire diameter?

[02_chevy]

33'S with 3.73's

[HARDTRAILZ]

im running 33's with 3.73s.

I would guess he has 33s w 3.73 and I did not have that poor of MPG with that setup.

[Trail X]

Yeah, if it was 33s and 3.42s I would be worried that the TCC was never engaging.

Still something for you to monitor Dan, watch the torque converter lockup signal with a scangauge and ensure it is locking up. If it isn't, it could be a big source of bad interstate gas mileage.