So my engine started running really rough, like barley chugging along. Pulled over pulled codes. Said it was misfire. I got the plugs, wires and coil pack replaced. I also did idle air control because of codes as well. But anyways, I replaced all of that and still have a cylinder 1 and 3 misfire. I myself am stumped and even have my mechanic stumped as well. HELP!!! PLEASE!!!

first up - what year, model of Subaru? how many miles?

what did you use for parts?

and yes, it DOES matter

plugs should be NGK copper cores, at the correct gap - anything else is just a waste of money, and possibly part of the problem
Wires should be OEM or NGK - anything else is going to be garbage on a Subaru
coil pak - aftermarket are potentially problematic... OEM is a far better choice, even a used one.

 

2002 subaru outback 4 cyl according to profile

jumped timing?

On 5/20/2022 at 10:36 PM, Rafiki said:

So my engine started running really rough, like barley chugging along. Pulled over pulled codes. Said it was misfire. I got the plugs, wires and coil pack replaced. I also did idle air control because of codes as well. But anyways, I replaced all of that and still have a cylinder 1 and 3 misfire. I myself am stumped and even have my mechanic stumped as well. HELP!!! PLEASE!!!

 

What he said - check timing belt. pull the front cover and check the belt, tensioner and all idlers. Install new subaru or AISIN timing kit only. The original pulleys probably still in there are in poor condition gauranteed.

list *all* codes that were present. 

What brand wires and plugs?  Subaru/NGK plugs and wires only. Though if there are additional issues (other codes and both misfires on the same side this probably isn’t the issue. 

I agree with the diagnoses above, but don't forget the EGR ..... overlooked many times for multiple misfires. Sometimes stuck open all the time, other times very SLOW to close, so after engine warms up, you get the low rough idle condition as well as multiple misfires.