just got back from afganistan after 7 long hot months. my evo has been stored in the garage the entire time. after the first drive the car stutters at exactly 10 psi all the way through 20 psi. anything below that it pulls fine. it doesnt feel like the fuel cut off because it doesnt have the hit the brick wall feeling it will still excellerate through the shudder it just lacks the same power. ive already changed the gas and spark plugs out and there was no difference. ive tried disconnecting the computer for 5 minutes thinking maybe it needed resetting due to the old gas which did smell bad after 7 months. i replaced the hoses on my hallman mbc and checked all band clamps for tightness due to possible boost leak. is it possible i still have a boost leak somewhere? ive ran a quater tank of good gas through the motor already with no change. evrything idles fine, i have the normal bolt ons exhaust, mbc, down pipe, dyno flash tune(mail in), injen intake. any help on this matter would greatly be appreciated.

 

7 months parked in the Northeast, maybe a varmit bit thru some electronics, and made a nest somewhere. Thanks for serving our Country, and welcome back.

 

Not sure man, sounds like gas, but thats not it. Try taking it easy for a while(keep using good gas) and see what happens. Sorry cant be more help to you. What branch u in?

 

gald to be back im in the navy

 

Sounds like you running base wastegate boost

 

not wastegate boost, he is hitting 20 psi, just studdering.. you may have some crap in your fuel lines... try running some fuel injector cleaner thru it and see if that helps.... what about your air filter ? wires ? just some suggestions.... but i would definitely start with the cleaner and filter maybe even throw some octane boost in it

 

didnt try injector cleaner, did clean the air filter sounds like a good idea. will try thanks

 

ran the car cold and didnt have any problems, everything boosted fine on the way to the parts store. as soon as it reaches normal operating temp the studdering comes back. added fuel system cleaner. its weird because it happens at exactly 10 psi on the bosst gauge. anybody have any other suggestions??

 

might try changin the plugs too.

 

replaced the plugs the first day with no change

 

the fuel in the lines might have gelled a bit. you might have to have the injectors cleaned, the fuel cleaner won't help what is already bad.

 

It sounds like a boost leak to me.

 

suggest that u run the tank to empty and fill up some fresh gas...

 

i drained the tank and filled it with fresh 93 octane the first day back. what i did forget to mention was the battery died while i was away could that have done something to the tune and pulled some timeing. like i mentioned when its cold it runs great till about 19 psi after it reaches operating temp it stutters from between 10 and 12 psi to 21 psi. feels like its starving for fuel. which leads me to believe its timming or something with the fuel or feul system. i checked all hoses for leaks. it doesnt have a problem hitting 21 psi which is where my mbc is set to. so id ont think its a boost leak.

 

A boost leak doesn't have to be very big to overfuel the engine and cause stuttering. It also won't always affect the overall amount of boost. If you are serious about finding your problem you should be checking everything that is suggested.