My check engine light comes on a couple of minutes into driving. It's accompanied by a rough, slightly bucking, engine. It seems to smooth out but the light stays on for the rest of the drive. I ran codes and got a 326. When I search online for Ford code 326, I get 326, and EGR problem, or P0326, a knock sensor problem. It doesn't seem like EGR would be causing rough running, but that maybe a knock sensor would? Anybody had this? The car's a 1995 SC. Thank, in advance, for your help.