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Bad gas milage and no power

Bad gas milage and no power

Postby stellarchevy [OP] » Oct 13 2012, 3:59am

Hoping to find some really smart fellas on here!

Have some serious power loss and bad fuel milage on my Silverado 5.3L 4x4. Also when I approch a light the idle goes to approx 1000-1500 RPM before I get to a stop. I've had one set of codes like MAF/MAP sensors and a biometric sensor go off but have cleared them and they havent come back. I installed a new Banks Intake and a gibsons exhaust on the truck about 6 months ago but never bought a tune for it. I guess the truck started running like crap back then but now I really need to deal with it! Checked the fuel rail and everything is up to pressure. Im lost, no codes and I have no where to start.

CALL CHEVY'S Best

Thanks
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Re: Bad gas milage and no power

Postby lzn197 » Oct 13 2012, 5:59pm

You've got a vacuum leak. Intake gasket.
Gordon
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Re: Bad gas milage and no power

Postby swan810 » Oct 14 2012, 5:39am

Same thing happened to mine after intake and exhaust minus the throwing codes. I was running way rich, a custom tune fixed it all up for me. Good luck bud
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Re: Bad gas milage and no power

Postby stellarchevy [OP] » Oct 14 2012, 6:05am

Custom tune? Perhaps a diablo or bully dog gt?
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Re: Bad gas milage and no power

Postby swan810 » Oct 14 2012, 6:32am

Negative on the bully. EFI live from blackbearperformance.com or diablo intune/trinity from diablew are your winners. I have the EFI live one and am happy. It has to be something that u can log data from your truck and have one of these geniuses adjust all you settings. They have to get deep in the codes of the computer, so those pre loaded jobs won't fix your problem
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Re: Bad gas milage and no power

Postby onlyhalfevil » Dec 11 2012, 6:10pm

Im having the same issues with my 94 Sierra. All my gaskets are good and I have no leaks. Its bone stock, with fresh plugs, wires, cap, rotor and ignition module. And do these tuners work on older k1500s? Cuz Id like to get more power and less galllons to the mile.
Have you towed a F**d lately???
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Re: Bad gas milage and no power

Postby Baker » Dec 12 2012, 1:04am

lzn197 wrote:You've got a vacuum leak. Intake gasket.



HUGE +1 on this ^

same thing with my sister 95 jimmy... like identical, high idle and every thing. have a garage smoke it
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Re: Bad gas milage and no power

Postby onlyhalfevil » Dec 12 2012, 1:29am

My idle isn't high. In fact, my idle is pretty low. Like 300 to 400 rpms at idle while in park and at op temp.
Have you towed a F**d lately???
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