I have a 99 ej25 with a ton of miles but it had been rebuilt (with receipts) when I bought it. Recently I noticed it shaking like crazy when it was stopped and finally it through a code, miss fire number 4. imagine that. So i went through the typical things, plugs, wires, checking the ground, sea foam, injectors, timing, etc etc etc. Nothing helped. I got to thinking, I bet i have a burnt or sticky valve. I cranked it up and put a dollar bill near the exhaust it sucks the dollar bill in and turned it black. So i decided to pull the number 4 injector and see if it would stop. well... it didn't. So i plugged it back in and pulled the number 2 injector. the suction stopped. That is odd. I wound't figure that a burnt or non working valve on one cylinder would cause a code on another. At this point i am not sure what i am going to do. I just put a brand new set of snow tires on her 50 miles ago. I may just drive it until I dies.
IF anyone has any suggestions on this please feel free to give me some hints or advice.