2003 lb7 keeps giving maf code.

Ineedhelp

New member
Sep 8, 2018
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Recently blocked the egr and removed the vacuum pump and intake heater. Been getting maf code since. New sensor. Same deal. Only throws the code when I start it. Pulling 53-56 g/s flow at idle. This is driving me nuts having to reset the light every time I start my pickup.
 

2004LB7

Well-known member
Dec 15, 2010
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Norcal
At start up the ecm goes through the egr checks. It is looking for a drop in air flow since some of it will be provided by the egr. If it is blocked then it won't see the drop and may trigger the code. Would likely get egr codes too

Need to have the tune adjusted for the changes
 

Ineedhelp

New member
Sep 8, 2018
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Had it tuned after and spoke to the tuner he suggested wiring problem but I can’t find anything wrong there. I have a device that reads the flow and can’t see that as the problem.
 

2004LB7

Well-known member
Dec 15, 2010
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Norcal
53-56 g/s does seem a little high. Shouldn't it be closer to 40ish.

Stock intake?
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,611
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Mid Michigan
Well, there's your first mistake. K&N intakes are terrible for these trucks.
Have you put the stock intake back on to see if the code comes up again?