gtoherd64

my 98 outback has a driveability problem, but only when cold. This morn I got in it, started it & it just sat there & wanted to shut off. I tried to back it up but it just sat there, and the engine stuttered. After a few minutes, I was able to get it to move, and then drove the 1/4 mile to the bottom of my street, then tried to up a hill. It sat at the bottom of the hill & for about one minute would not take revs at all. Then, finally, it acted like it was shot from a cannon, and then ran normally for 12 miles to my mechanic's shop. He put his code machine on it & it said engine was misfiring on 3 of the 4 cylinders (it's the 2.5). He told me to drive it 30 miles & bring it back. I did, he checked it & this time no codes at all, and the check engine light was off.. My son usually drives it & he said that after it warmed up, it ran good, but his $6 code checker still said one cylinder was misfiring. HELP!!