My truck just had the stock muffler fail @ 172k miles. I put a Magnaflow muffler on it yesterday. The battery was disconnected during the install. Upon firing it up the check engine light came on. I can't believe it is a back pressure issue because it must have more with a muffler than it did with a gaping hole in the bottom of the stock one for the last week. Any ideas?

 

did you check what code it is? might not be the exhaust at all.

 

I don't have a scan tool, but it ran rough for about 30 seconds on start-up then cleared up and ran great.

 

Very true^^ it would help alot and we could help you more knowing what the code was.

 

By doing the key trick I came up with p0441 and p 0522.

 

https://dodgeforum.com/forum/3rd-gen...code-list.html