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Discussion Starter · #1 · (Edited)
Recently purchased a 07.5lmm with 130k miles and had efi live mbrp egr delete done by merchant automotive. When driving on a flat grade at a constant speed the transmission will downshift from 5th gear to 4th gear when it's not needed causing the RPM's to jump. What's the deal? I don't recal it doing this prior to efi live.
 

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How fast are you going when you in 5th gear and how many RPM's. My 2500HD 6.0 use to do the same thing but I was on the freeway and it would kick in and out of OD real annoying when you already get crappy gas mileage.

What did the merchant automotive guy say when you reported the problems to him.
 

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You sure it's not in 6th gear downshifting into 5th? How many rpms is it running at when this happens?
 

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Discussion Starter · #4 ·
When it happens im going between 25 and 45mph, i check the gears by switching to manual before and after the jump and its 5th and 4th gear. The rpms go from 1400 to 1600 when it downshifts. As soon as i hit 50mph+ it will shift to 6th gear and stay there no problem.

I have yet to call merchant but i will tomorrow and see what they say, im sure theyll blame it on anything but their tuning. After hours of research i have come to the conclusion its either the fuel filter, trans screw on filter, CP3 or i need a lift pump. Any ideas would be greatly appreciated!
 
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