My 2003 had a leaking heater core. I replaced core and now it's throwing #2 cylinder misfire. Was fine before removal of heater core. To make worse took to dealership to do airbags and check problem and they replaced throttle body(I told them that wasn't it) took home died again. 3rd trip back replaced computer. Guess what died again. Only took to them because I didn't have time what a mistake!!! Solutions?

 

The only thing I can think of is that you damaged the wire coming out of the ECU that fires the #2 ignition coil. But the ECU connector has a cover on it. So I don't know what you could have done to make cylinder 2 misfire. Cylinder 2 is by the radiator, passenger side corner.

I think this is just unfortunate timing. Swap the ignition coil on cylinder 2 with 4 or 6 and see what happens.