I have a 2002 wrx I bought about a week ago the check eng light came on so I scanned it to see what was going on and it said misfire detected in cyl 1-4 and my turbo won't boost until 4500 rpms. I changed ground and power cables to the battery and got a new bat to. I cleaned the mas air sen and changed the plugs. The weird thing is while I'm driving the car if I start to go up a hill or down the hill it will cut out!! If anyone has any ideas it could really help thanks!!