My RX7 started running really bad a few days ago. the rpms were very sluggish, I had no power. I thought I might have blown the engine but I checked the compression and it's alright. I checked the spark to and it seemed a little weak. When I rebuilt the engine 3 months ago it had a nice arc. I was wondering if coils go bad. Do you guys have any sugestions on what I can do to diagnose the problem. The leaner I make the better it runs. The spark plugs where charcoal looking so it's running very rich. I feels like the spark plugs are working. Any suggestions.