I have just recently purchased a modified 03 Evo VIII from a dealer who had no idea what's been done to it. I have only had the car for a couple of months and have been sorting through some of the problems and trying to figure out what has been done. I have purchased a boost, fuel, wide band and oil pressure gauge but have installed them yet (reall really need to but...). I know the car has a DP, intake, 3" exhaust, MBC, FMIC, BOV and turbo but I can't tell if it has a tune and if so whose it is or bigger injectors. So for belating my issue but I figure the more back story the more info you have in helping.

So the time before last I started to have a choppy interrupted heavy acceleration. Then it went away. So I picked up a new set of plugs and took it back out, now it does it constantly.... I can start to spool up under mild acceleration and it will hold boost. But if I give it more then half throttle it will start to buck like holy hell. It will cut out boost and feel like it has gone to zero for a fraction of a second then pick back up and start to run for a fraction of a second and then fall back on it's face. I have tried it in all gears under different acceleration scenarios and it seems to me like the BOV has died. I personally have never seen one flow both ways but I know it's not compressor surge and I plan on checking for any leaks in the system with a boost check. But was looking for any help on this problem.

Thanks
Justin

P.S. I have searched and read a bunch of info on this site but haven't found this exact problem so by default no solution.

 

U should spend the money for evoscan and a tactrix cable or a tune. Sounds like domineering flashes it back to stock with some modifications . My first guess is fuel cut. My second guess is some major timing/fuel table woes . U need not drive the machine in this condition til u can log at the very least . And def boost leak test it

 

I hate auto correct in this Damn phone. Sounds like someone flashed back to stock perhaps and didn't raise fuel cut limits

 

Yeah I could see it being fuel cut, but I haven't had this problem until now. And I haven't done anything that would have taken it out. But I will check into getting an evoscan. I mean anything is possible... Thanks

 

Do a boost leak test. If I'm understanding you correctly I'm having the same issues. My throttle body shaft seals are shot. Yours could be something as simple as a loose boot. But I'm not saying it is a boost leak. Just a possibility.

 

check both sides of your IC piping...