Ok guys I recently changed the headgasket and timing belt on my 99 gsr motor and after the job was all done I was throwing these 2 codes (71 and 74.....cylinder 1 and 4 misfire). I figured **** the spark plugs are old so I changed them. I re-set the ecu and checked the codes and nothing (meaning the code went away). Now I know many of you may think why are you telling us this but I want to know if there is anything else I need to check just to make sure. Could the spark plugs be the reason why it was throwing a code

In addition I was running a little off timing and I adjusted it back to correct setting. I appreciate all input and thank you guys in advance.

 

Need some input guys.....