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Killed my MPG, what could get it back?

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Old Mar 2, 2008 | 11:28 PM
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Forklift's Avatar
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Default Killed my MPG, what could get it back?

I did a Summit Racing 3" intermediate pipe dual out Summit Racing (IMCO) system on my 04 Silverado ex-cab 4.8L. You can see right in one side of it and out the other. Its one chamber and no baffles. It sounds ok and I wasnt looking for much, but I was hoping for a few extra hp(2-5 maybe) and mainly a better sound. Summit sent me the wrong one and I tried to install it and left the tailpipes off after getting the intermediate pipe and muffler to work ok. So.......

So did the pipe kill it or did the muffler or lack of pipes after the muffler?
What would give a LS truck a good sound?
Should I ditch the 3" and go back to stock 2.5?
Help
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Old Mar 3, 2008 | 12:23 AM
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really if your putting a free flow muffler on it with less restriction you should be picking up MPG since it is more efficient. I doubt that a muffler would cause the car to have messed up A/F ratio due to something so small. Maybe you just put your foot into it now that you have a louder sounding truck and you like it.
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Old Mar 3, 2008 | 01:31 AM
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You think you have bad gas mileage now....don't put a cam in there.
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Old Mar 3, 2008 | 10:06 AM
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well it went from about 21 highway to 15 and my foot has been out of it to try and get it back. With gas going up and me having a 50 mile round trip daily, Im forced to take the wifes Scion , this sucks. I was actually thinking about a cam at some time or another, maybe a takeout from a vette
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Old Mar 3, 2008 | 11:18 AM
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What gears are you running? probly 3.73's, swap out to 4.10's
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Old Mar 3, 2008 | 12:10 PM
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I havent checked yet, but I should. Why would going to a higher gear make it better when all I do is highway driving?
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Old Mar 3, 2008 | 12:31 PM
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Originally Posted by JimsWS6
What gears are you running? probly 3.73's, swap out to 4.10's
4.10's would get worse mileage. mabye its a problem with the o2's getting oxygen up to them. thats really the only thig i can think of, like a tuning issue
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