can a really bad exhaust leak reduce your gas mileage by a big amount?

TIA

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*89 Trans Am GTA
*Moderator at www.transamgta.com

To hell with the GM vs Ford war. We must unite, as brothers to fight the plague that is overtaking the world...RICE

Tony

 

Exhaust leak that is before the Oxygen sensor can caouse the sensor to have an inaccurate reading; therefore, changing the signal to the ECM causing it to enrich the mixture.


I would not say you would notice a big difference in MPG. Myself i had an exhaust leak at the header flange (gasket like) for almost 1 year before I fixed it. What really pissed me off was not my MPG but anoyying exhaust leak sound and the fumes.

Hope this helps.


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89Iroc, 305 TPI, WC T5, 3.08 Posi, Headers, Hooker Y-Pipe, 3 inch over the axle, Flowmaster 80, No Cat, Aluminium Driveshaft, Ported Plenum, Air Foil, K&N, AFPR, All free mods,

 

He is correct, exhaust leaks act as a "venturi" and pull outside air into the exhaust stream, and can fool the ECM that is lean via the O2 sensor.

I also know a person that ran on the dyno, then realized he had a header leak. Fixed the leak and gained 17 RWHP, dyno proven. I know I will probably get flamed for this, cause some people have a hard time grasping concepts, but it was from a trustworthy source. (P.S. it was not a stock setup)

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