missing on number 2 cylinder

[PlenumBiscuit]

Just put a donor engine in it which i had to get unseized. It hasn't been driven yet but engine is running now but 2 days after i got it running it's missing on number 2 cylinder

Ive changed the plugs leads injectors and ecu? I spent a lot of time and money on it now any one know what else could be causing it to miss

 

[Not_An_Abba_Fan]

If you have had to unseize it, I'd be doing a compression test. Could be anything from a broken ring to a burnt or stuck valve.

Has it just started doing it? Try the coil packs.