Any ideas what I did wrong? I have a 2005 MCS with 133k miles. Just replaced a leaky valve cover gasket and the spark plug tube seals. Now it won't idle, jumps all over the place, and I get P1109 and P1242 fault codes.

To replace the valve cover gasket I had to remove the intercooler, intercooler brackets, ignition coil, spark plug wires. Nothing too crazy, it seemed to go very well, no real issues. Until it was put back together...

Any ideas?

 

Ok, so I probably need to count to 10 before posting panic-y stuff. I found another thread indicating a similar problem from poorly seated boots on the intercooler. Went and checked mine and one was folded under and not seated right.

Fixed that and all is good. It's amazing cars run at all!