I have a 2012 EB with a MBRP cat back exhaust, airaid intake, and custom tunes from MPT. Recently in my never ending pursuit of the right exhaust sound I had a shop chop my MBRP muffler off, and leave the exhaust dumped under the cab with only a resonator in place. Until I did this the truck ran like a champ, now under heavy acceleration from a stop the truck seems to make a fluttering sound from the exhaust and falls on its face until i hit approx 3300 RPM, then it takes off like a rocket ship. Any idea why its suddenly falling on its face? I contacted MPT about adjusting the tune due to the increased exhaust flow and they said it would be a negligible difference and that any adjustment would be unnecessary.

 

Bump, truck seems to surge back to normal around 2700RPM's. anyone have any idea what could be causing this? Would a TurboSmart BOV possibly help the situation of the factory BPV's letting air leak?

 

Can you have that same shop put that muffler and end pipe back on and see if that helps? It sounds like maybe there isn't enough back pressure until that 3k rpm range?? This is just a shot in the dark, but I saw no responses and thought I'd suggest it. It's what I'd try first if it rAn like a champ before the mod.

 

I agree you need backpressure very important!

 

NM

 

Up here in Canada we get this due to a collecting of water in the cooler. Cruising along the humidity condenses and then when the flow increases the engine gets a gulp of H2O. Engine stumbles until it clears or you back off the throttle. Fords fix is an air dam that covers about half the cooler