What the H____?!
Thread Starter
Burning Brakes
Joined: Dec 1999
Posts: 1,088
Likes: 0
From: Silver Spring, Md.
What the H____?!
My '05 Z51 cpe has suddenly (or at least I've recently noticed) that my gas mileage has dropped about half. After watching the gauge head towards the half-tank mark I started keeping track and combined driving was about 18mpg; I'm used to high 20's, especially with all the hwy driving I do, and taking a week to go through a half tank of gas vs. 2 days. Also noticed when accelerating from low rpm a couple of times experienced valve rattle. No hard accelerating or really pushing the car, no mods to the engine, engine not burning oil or running hot, same gas, nothings changed except the "perceived" reduction in power at low rpm or accererating from 2-2.5 rpm. Is it possible my tunes gone wacky? Also I seem to hear "tick, tick, ticking" thru the speakers but doesn't seem to change frequency. Plugs and wires were changed about 15,000 mi. ago. Any thoughts appreciated.
Team Owner
Joined: Dec 2003
Posts: 57,408
Likes: 164
From: queensbury ny
sounds like crappy gas or a bad tune,or tune gone bad.I heard that thumping thru my speakers in my 05 when I had it too.Never did find out what it was,just swapped the radio 3 times under warranty.
Pro
Joined: Jul 2006
Posts: 608
Likes: 1
From: LZ IL
sounds like bad gas.
Did you know that if you run 87 oct that you stand to loose 4-5 MPG?
It's true. I did a test in both my 03 Tahoe and 07 C6. Though I was doing good running 87 oct and pulling back the tune in my Tahoe. Wrong. Lost 5 miles per gallon. Want the math. 300miles/18mpg=16.6gals@$4.24=$70.38
300miles/13mpg=23.0gals@3.99=$91.77
So all you people that run lower oct thinking your saving money.
Did you know that if you run 87 oct that you stand to loose 4-5 MPG?
It's true. I did a test in both my 03 Tahoe and 07 C6. Though I was doing good running 87 oct and pulling back the tune in my Tahoe. Wrong. Lost 5 miles per gallon. Want the math. 300miles/18mpg=16.6gals@$4.24=$70.38
300miles/13mpg=23.0gals@3.99=$91.77
So all you people that run lower oct thinking your saving money.
Racer
Joined: Oct 2006
Posts: 424
Likes: 1
From: WA
sounds like bad gas.
Did you know that if you run 87 oct that you stand to loose 4-5 MPG?
It's true. I did a test in both my 03 Tahoe and 07 C6. Though I was doing good running 87 oct and pulling back the tune in my Tahoe. Wrong. Lost 5 miles per gallon. Want the math. 300miles/18mpg=16.6gals@$4.24=$70.38
300miles/13mpg=23.0gals@3.99=$91.77
So all you people that run lower oct thinking your saving money.
Did you know that if you run 87 oct that you stand to loose 4-5 MPG?
It's true. I did a test in both my 03 Tahoe and 07 C6. Though I was doing good running 87 oct and pulling back the tune in my Tahoe. Wrong. Lost 5 miles per gallon. Want the math. 300miles/18mpg=16.6gals@$4.24=$70.38
300miles/13mpg=23.0gals@3.99=$91.77
So all you people that run lower oct thinking your saving money.
I did a similar test and lost a ton of mileage with the reg octane crap and 10% ethanol mix,
Thread Starter
Burning Brakes
Joined: Dec 1999
Posts: 1,088
Likes: 0
From: Silver Spring, Md.
Thanks guys. I thought about that but having used same station in past I didn't lean that hard on it as the issue. I'll throw in some torco and when it gets down below half (which shouldn't take too long
) I'll switch to another premium and see how it goes.
) I'll switch to another premium and see how it goes.
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