I have a 2003 trailblazer 4x4 with third row seats. while under hood working with another problem I pulled the wrong relay out. I pulled the fuel pump relay out while running and it shut off. when I put relay back in and stared it back up, it ran rough. check engine light is on and when I get above 30 it flashes. what can I do to fix the problem. went and had codes read. number 3 cylinder misfired.

 

I'd start with replacing the plug and checking the wire on the number three cyl