i have a 2003 evo 8 with roughly 87,000 miles... for the last few months the car will not make over 10psi with out having a horrible cut out.... it almost seems like it drops a cylinder... it still revs up while its bogging but coughs and sputters horrible... i did a boost leak test and the only thing was the throttle body seals were hissing a little bit above 15psi... changed the plugs gapped to .030 bpr7es... in neutral it will free rev fine with no problem... and i can drive it as long as i peddle it on or under 10 psi... gas mileage is normal. and there is no CEL even if i hold the gas through the cut out... im lost on this one, any one have an idea???

 

Does it happen only during our cold winters or also during the summer? I have been having a similar problem (only in the winter though, since I changed my turbo for a new stocker). I am no expert, but it seemes like when I got tunned my other turbo was on its way out, and the new one bows more than the old one, hence cuasing the turbo to boost more on a particular RPM load. I am not sure if my ECU pulls timing or opens the WG to lower boost. Mind you I don’t have a MBC, and my ECU controls boost.

Maybe I am way off since I do not know more details on your car, but it may be a boost/fuel cut or a vac line. Check the lines and/or get it tunned. Is your car 100% bone stock?

 

you can't boost over 10 psi? sounds like your running just off your wastegate...do you have a MBC?

 

try lowering the spark plug gap to about .024 or so... .030 is kinda high