Bosch irridiums. A zone didn't have the plain Jane champs, last time so I got these expensive ones

 

Hey it was my mechanic trashing the +4s not me!!!! HOWEVER, it did not solve the problem. Misfires occurred on 3 cylinders when it got on on the highway. Again at high RMS which is what I am thinking the whole power issue is relating too. Reset the codes and have not come back but I have not brought out onto the highway either where it takes the pedal all the way down to get it to 60. So I retract blaming it on the +4s and humbly come back to guys. I went ahead and took off the front O2 sensors for a test of the catalytic converter but did not notice any power improvement. I had put on new STI wires two years ago so I don't think it is the wires. So is the only thing left to consider the coil pack? Is there a way to test or is it just a process of elimination? How difficult of a job is it? Thanks for your help!