# truck runs better w/o maf sensor



## EdmonW750 (Feb 2, 2012)

So my buddies truck runs like crap when the mass air flow sensor is plugged in and when he unplugs it it runs better confuses the hell outta me. Any explanations?????


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## z24guy (Nov 27, 2010)

The MAF is probly screwed. When it is unplugged the ecu is running from pre-programmed fuel maps and not using information from the MAF or O2 sensor to decide on things like timing advance or fuel timing.

Take it in and get them to check it out with a decent scanner. Should be able to see the output from the MAF


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## Polaris425 (Dec 16, 2004)

^ Agreed. Sometimes you can clean them good w/ a cotton swab & some alcohol. If they are just dirty. If its done it's done though.

AutoZone will scan it for free.


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## mossyoak54 (Jan 16, 2012)

What type of truck is it? And yes cleaning it is the best try at first.


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## BruteForce407 (Apr 1, 2010)

Agree with above sometimes you can clean them. And unplugged it will sometimes run better but not ideal. Get it scanned or try cleaning it.


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## EdmonW750 (Feb 2, 2012)

Its a 97 z71 with a 350 and he had it scanned and autozone said it could be like the maf sensor or the o2 sensors or something else he has a friend that has a better scanner and hes goin to get him to see what the deal is


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## EdmonW750 (Feb 2, 2012)

but clearly theres a problem with the maf sensor


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## mossyoak54 (Jan 16, 2012)

Well o2 sensor can make things act funny. It works in conjunction with your maf. O2 sensors can be cleaned also. I had a truck brought in one time that had an issue with running rich and a cleaning of the sensor helped. They get carbon build up. I always believe try the easy stuff first and invest in obdII scanner so you can try things and clear codes and see if that's it. Just my .02


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## Stogi (Feb 24, 2010)

Best thing to do on a truck that old is to change out the MAF and o2 sensors at the same time. If you clean the maf and still have a slow o2 your just wasting time.


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## gav09 (Feb 1, 2012)

make sure you don't break the little sensor wires on the MAF when you clean it. I usually just clean them with carb cleaner. If there is a K&N filter make sure its not over oiled that get them dirty real fast. 
If it still runs bad replace MAF


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