My gas mileage sucks
10-29-2004, 11:00 AM
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My gas mileage sucks Recently I have had to try to get over 200 miles per tank. Right after i put my headers on I my idle air motor went out. I thought that was my problem with gas mileage. Well relplaced that got better for a little then went to crap again, so I replaced my 02's. It still sucks. I have my rear 02's taken out and my air and egr system removed so I have a check engine light. What could cause my gas mileage to suck so bad still.
Chris
Chris
10-29-2004, 11:24 AM
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I got headers on about a month ago and my mpg went down too. I posted here and found out mine is from the engine running to rich. Yours might be running rich too, especially if the exhaust smells bad. I noticed yesterday that mine shifts in the low 5000 rpms when almost punched but it used to shift high 5000 rpms before my headers were installed. Is yours doing the same thing or is yours a manual?
10-29-2004, 11:24 AM
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Originally Posted by Mtnm2
Recently I have had to try to get over 200 miles per tank. Right after i put my headers on I my idle air motor went out. I thought that was my problem with gas mileage. Well relplaced that got better for a little then went to crap again, so I replaced my 02's. It still sucks. I have my rear 02's taken out and my air and egr system removed so I have a check engine light. What could cause my gas mileage to suck so bad still.
Chris
Chris
You have no rear o2's (do you have o2 SIMMs in place of them?) did you plug the holes that the o2’s use to be in? Or did you get an off-road y-pipe?
Your air injection tubs are off the manifolds? (Are the holes in the manifold plugged and sealed?) Or are your headers emission delete?
You removed your EGR system? You removed the tube that runs from the intake in to EGR valve then back to the manifold? How did you seal these two holes off? Intake and manifold? Or are your headers emission delete? Did you swap the intake for an ls6 or vett ls1 intake with no EGR hole?
If you did not cover any of these holes I don’t see how your car would run? You must turn these codes you are getting off. If you want the car to run right, if you can’t get tuning you need to at least hook the EGR and AIR backup and buy a set of o2 SIMMs. If you in fact got headers with the emission delete you will have to get a tune.
Give us more details about your car?
10-29-2004, 01:21 PM
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Removing EGR increases pumping effort in the low
cruise operating area and will cost you MPG.
Headers often want tuned, and often cause O2
sensor problems. You apparently already have seen
that good O2s improve things; how about trying
the better, 'vette rears and see how that does?
Corvette Rear O2 Sensors:
Bosch 13111
Denso DEN 234-4087
cruise operating area and will cost you MPG.
Headers often want tuned, and often cause O2
sensor problems. You apparently already have seen
that good O2s improve things; how about trying
the better, 'vette rears and see how that does?
Corvette Rear O2 Sensors:
Bosch 13111
Denso DEN 234-4087
Last edited by jimmyblue; 10-29-2004 at 03:23 PM.
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10-29-2004, 01:36 PM
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I have my Headers on and No cats, no emissions, and I still get 20 in town and almost 30 on the highway, and I am on a stock tune, But I also have a M6 
, But my dads T/A gets 25 on the highway and 18 intown with his and his is an A4 with a Cam and Converter.
Dan
, But my dads T/A gets 25 on the highway and 18 intown with his and his is an A4 with a Cam and Converter.Dan
10-29-2004, 02:22 PM
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Just to give you an idea of how rich...on a diablo predator: bank 1&3 should be btwn 880-910. lower=lean,higher=rich. Mine went from 890(before) to 955 after my headers. I am still in the process of carefully leaning it out, right now they are down in the 920's and it runs way better.
10-30-2004, 11:46 AM
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sorry to burst ya'lls bubble but somehow i'm getting 25 mpg average...w/moderate throttling...looks like i'll keep it that way for a while. Yes I know its stock but when I can go 330 miles on a tank...why kill it?
10-31-2004, 03:09 PM
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I only get just over 21 mostly highway 
, 01 ws6 M6 totally stock. I think this is low, but the car runs great, and the plugs look good. Does anybody else think this is low mileage for a stock car. Also has new tires running 32psi, if that makes a difference.
, 01 ws6 M6 totally stock. I think this is low, but the car runs great, and the plugs look good. Does anybody else think this is low mileage for a stock car. Also has new tires running 32psi, if that makes a difference. 