Hey I have a early 99 7.3 and I was talking to someone on here who seems to be very knowledgeable about it and I just wanted a few different ideas.. so my truck was blowing a lot of blue smoke and misfiring. But sometimes it was intermittent. For example I got on it last week and when I put it in park it wasn't smoking no miss. When I fired it back up it was doing it all over again. So I got a buddies scan tool and it was cylinder #5 down (contribution test). So I went ahead and replaced it. But still no luck. So I ripped off the vc and dropped each injector on the right bank. All but #5 made a difference. The only thing that happened was the smoke stopped? I changed it again last night and it still smoked. So I cursed and sweared and left it. Now today I plugged it in and let it idle for about 45 minutes. And wasn't smoking nearly as bad! Plus is 10 degrees colder here (Celsius) I was wondering is it a broken ring? It does have a chugging blow by. I couldn't tap the mallet on the injector very hard because the things too bulky with the cowl in the way! Could it not be seated properly? I'm really hoping it didn't blow a ring!!