slowly droping MPG

pastor scott.com · July 2, 2005

On my 04 burb 5.3 with only 4500 miles on it , is slowly getting worse MPG around town. It went from 13-14 to aorund 10 -11 MPG. Can it be the 10% ethonal or something wrong after break it? Any sugestions ? Should I bring it in for check up at dealer ?

thanks

Scott

GM-Tech · July 2, 2005

Ethanol definitely requires more fuel to do the same job. So, have you just started using this?

In my experience, poor gas mileage complaints are the result of driving conditions and habits. In all the years I have worked on cars, I have NEVER found a problem in the vehicle that would account for poor gas mileage.

We usually get these complaints when the price of gas goes up. And most people do not accurately monitor their mileage. They come in saying, "I drove to work all week and used half a tank when I normally use 1/4 of a tank" and they have absolutely no clue how many miles they actually drove, or how many gallons they consumed.

Yeah, you can take it in. I think it's probably a waste of time.

Cool Zr2 · July 2, 2005

Yeah, you can take it in. I think it's probably a waste of time.

<{POST_SNAPBACK}>

Lol, thats gotta be the best quote ever!!!

I don't think you can judge your gas mileage on a 4500 mile truck. I'd say if you got 14 mpg around town then there was something wrong with that, if your getting 11, sounds normal. Hell, my dads 03 suburban 5.3 gets 10 city and about 16 hwy.

MrQuadrasteer · July 3, 2005

@ ZR2

It's great having Tech here, ain't it Shoots ya straight

I know I appreciate your participation, Tech (that all sounded like it coulda been sarcastic !!!)

Yeah, Scott, I'm thinking a few more miles. If EVERYTHING was identical and the mpg fell off.... did anything else change- idle ?? Any hiccups at any rpm/load/speed/accel/deccel, etc ?? Check your tire pressure ?? Braking even ??

Got a few friends with NEW trucks, under 10k miles, that have had knock sensors, O2s, MAFs go bad.... chit happens

No ses, I presume

GM-Tech · July 3, 2005

I'm thinking that with 4500 miles on it, gas mileage should have improved over when it was new, not dropped.

I'd guess at that mileage, it's about as broken in as it's going to get and a few more thousand miles isn't going to improve mileage a detectable amount.

mmmikkke · July 3, 2005

I'm thinking that with 4500 miles on it, gas mileage should have improved over when it was new, not dropped.

I'd guess at that mileage, it's about as broken in as it's going to get and a few more thousand miles isn't going to improve mileage a detectable amount.

<{POST_SNAPBACK}>

I think my 6.0 came into its own, and its mileage improved, at about 7000 miles. But my break-in was easy. Others might break theirs in quicker.

Irregardless, I think your mention of ethanol dropping your mileage is the likely cause.

Ethanol should reduce your MPG, and your maximum torque, by about 4%, but results vary. See if you can find some real gasoline.

MrQuadrasteer · July 3, 2005

See, I'm with Mike- I really don't think my engine was done breakin' in until 7000, or more Actually, maybe 10k, cuz that's when I kinda noticed a couple things not jivin' for me

But anyway, I have heard a number of folks claiming these new LSx truck motors have unusually long break-in periods... Mine had a moderate break-in; I was fairly easy on it but didn't baby it. No redline runs, but a few seconds of wot every so often

jamashke · July 5, 2005

I got my 01 at 25k and ran like a top. My 04 has about 21k on it now and is just starting to run my like 01. I did baby it for about 5k. So is my engine broke in yet? I am wondering. But for the mileage to drop? Question...dirt roads?