I have an issue with my 95 WRX with an EJ20T. Under moderate to WOT it gets really jerky, and bucks... Seems fine with first started up... Drives normally if just putting around. What could it be? All I know about the car is it has an exhaust. I am assuming the rest is stock. Also, I am in Japan if that makes an difference.

It does this in all gears.

 

Sounds like over boost causing boost cut. Check for boost leaks on all the pipes, mainly intercooler and pipes from the boost control solenoid.

 

Will do. You can hear the turbo spooling quite a bit... My buddy has a stock one, and you can't really hear the turbo at all. I'll take a look tomorrow. Anything else I should check?

 

Thats about it. I reackon you will find a burst/split pipe somewhere.

 

Okay, sounds good. Ill take a look today.

 

possibly the maf (mass airflow sensor)
this was the problem with mine. it ran fine when off boost ie just running around but when you floored the throttle it jerked and didnt want to go anywhere then it would go as normal then jerk again. if you have the green label airflow sensor check that as they are prone to it

 

Will do! I don't have a Check Engine Light on though. I'll check anyway though.