Gettin about 17 mpg on stock set up
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Joined: Oct 2002
Posts: 543
From: Cincinnati, OH
Gettin about 17 mpg on stock set up
Gettin about 17 mpg on stock set up...is this normal? I just got a magnaflow muffler installed and i dont think it should have changed anything.... but shouldnt i be able to get better gas mileage with a stock setup? It's a 1996 LT1 M6 with like 57,000 on it. would a CAI help? I do tend to rev out till liek 3000 RPM through shifts. When i cruise at 70 in 6th i only rev about 1800 RPM. Would it be wiser to cruise in 5th? Is it worth buying hte CAGS for $30 and gettin rid of that? Just need some points of view...thanks
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Joined: Nov 2002
Posts: 1,332
From: Louisville KY
I'm getting just over 17 mpg on my car, but I have a cracked stock exhaust manifold (excuse for long-tubes 
) so I may be running a little rich from that. My 96 Z28 I had (RIP) got no worse than 19 mpg and it was all stock except catback. I would check the O2's, plugs, wires, coil, clean airfilter, etc. Shifting over or about 3k doesn't help either, it's going to use less gas at lower RPMs at a higher gear than higher RPMs at a lower gear. Which is why cars with 3.73's and 4.10's get worse mileage.
) so I may be running a little rich from that. My 96 Z28 I had (RIP) got no worse than 19 mpg and it was all stock except catback. I would check the O2's, plugs, wires, coil, clean airfilter, etc. Shifting over or about 3k doesn't help either, it's going to use less gas at lower RPMs at a higher gear than higher RPMs at a lower gear. Which is why cars with 3.73's and 4.10's get worse mileage.
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Joined: Sep 2001
Posts: 389
From: Palmetto FL/Tallahassee FL
Well, if you get on it a lot then that's not such bad mileage. I would check/change plugs, wires, and airfilter though just for good measure. If you have acess to a diagnostic tool you could also check the readings from the o2 sensors.
Also, CAGS is there to improve gas mileage - diabling it won't help. BUT if you want to get rid of that PITA just because it bothers you then DO NOT buy the CAGS ELIMINATOR. It is a complete waste of money! On 96 and newer obdII cars you can disable the CAGS with a resistor from radio shack - a whole pack of 5 or so costs less than a buck. Just unplug the CAGS harness and plug the two prongs of the resistor into the computer side of the harnes and then tape everything up and outta the way. Viola, the computer thinks the harness is still hooked up because the resistance is there (no codes but "skip shift" light still comes on) and the trans doesn't force you into third. Best bang for the buck mod I ever did
Do a search to come up with the ohms rating of the resistor.. sorry I don't remember.
On a related issue, anyone know how to track down a leaky injector?
Also, CAGS is there to improve gas mileage - diabling it won't help. BUT if you want to get rid of that PITA just because it bothers you then DO NOT buy the CAGS ELIMINATOR. It is a complete waste of money! On 96 and newer obdII cars you can disable the CAGS with a resistor from radio shack - a whole pack of 5 or so costs less than a buck. Just unplug the CAGS harness and plug the two prongs of the resistor into the computer side of the harnes and then tape everything up and outta the way. Viola, the computer thinks the harness is still hooked up because the resistance is there (no codes but "skip shift" light still comes on) and the trans doesn't force you into third. Best bang for the buck mod I ever did
Do a search to come up with the ohms rating of the resistor.. sorry I don't remember.
On a related issue, anyone know how to track down a leaky injector?
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Joined: Feb 2003
Posts: 216
From: Perry, GA
If I were you I would definetly check the plugs and wires and possibly shift sooner. I have an A4 and even with 97,000 miles on the original plugs and wires I get 18.5mpg when I am raising hell and I have gotten 22mpg with mixed city and highway driving.
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Joined: Jan 2001
Posts: 2,148
From: Bay Area, CA
3k RPM shift points should not make a difference, but why do you rev so high? I dont even rev like that in my 2.4L straight 6, these cars have the torque to shift alot sooner than that.
If your hitting an honest 3k in first you wont have CAGS come on anyway.
Start with maintenance items like mentioned, the CAT has got maybe 30k left on it as well, so you could get to that next.
If your hitting an honest 3k in first you wont have CAGS come on anyway.
Start with maintenance items like mentioned, the CAT has got maybe 30k left on it as well, so you could get to that next.
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Joined: Dec 2002
Posts: 278
From: Corona/LA
a leaking y-pipe and a cracked AIR injection tube on the passenger side netted me about 11mpg. 
check for exhaust leaks, if not, what was said above - plugs, wires, o2s, and check the cat. how does your exhaust smell?
check for exhaust leaks, if not, what was said above - plugs, wires, o2s, and check the cat. how does your exhaust smell?
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Joined: Oct 2002
Posts: 543
From: Cincinnati, OH
mineralwater
My exhaust wreaks once i get it in the garage and shut it off. I sit in the room just inside the garage and use the computer and i can smell the fumes, so i would say it is pretty strong, but I figured it was strong because it was a v8 being parked in a garage. I never smell my mom's volvo i-5 and i never smelt my dodge avenger which was a i-4. So i'm not sure what to think of of the smell. I've decided to just granny it and shift before the skip shift and then 2000 - 2500 for all my other shifts. I'll see how this week goes, if it doesn't improve i'll move on to checking the other stuff. Thanks for all the input everyone, hopefully i can find out where my problems are.
