I have an 04 Evo with these mods, 3" UR TBE, Injen intake w/ UICP, and single solenoid TurboXS MBC. Well yesterday I recieved my Hallman MBC to replace my crappy TurboXS one and a fuel pump to complete my mods before I go to get my tune. I installed the fuel pump and started the car. It turned over about 4 times before it started, I'm guessing becuase the fuel pressure had to build in the lines. Well it idled fine. Then I swapped the MBC's and went to take her out for a spin to adjust the boost. Well the car is running like crap. If I ease into the gas it goes OK till about 3k rpm then it stutters and makes crazy popping sounds (from the engine bay) and if I stomp it ( WOT) while parked the car pops and stutters terribly at about 4500 RPM's. Someone please help me out here !!!

 

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Anybody???

 

Check spark plugs

 

Fixed, the stock fuel come with a white or really light gray spacer that goes on the nipple on the opposite end of the filter (where the pump connects with the big white plastic assembly). Well it didnt look like it fit very well on the Walbro so I didnt put it on. I removed the Walbro,put the spacer on and it works like a charm. I didnt see any notes in any of the "How to's " about this spacer so I didnt think it was needed, Oh well. Thanks anyway.