Any Idea?.....3406E Cat Problems

My husband has a 3406E C-15 that was in an accident in May 2007 and has had problems every since. We cant figure out what is wrong!

What it is doing: It lunges and lopes. It doesnt do it until it reaches operating temperature and it only does it on the foot feed. Not cruise control. Sometimes it acts as if it looses power and then sometimes it acts as if it gains power on its own, while holding the foot pedal steady.

What we have done to try to fix it: We have put it on the dyno a couple dozen times to no avail. The first time it said #1 and #2 injectors were bad. So we replaced them and hooked it back up to the dyno and it still said #1 was bad so we swapped #1 & #2 and it still said it. So CAT told us it had to be the wiring harness from the ecm to the injectors, so we replaced that. Still not fixed. Then we were told that since it does it on the foot feed and not cruise that it was the throttle position sensor. So we replaced it and still not fixed! Then we were told it was the ECM so we replaced that and it worked for about a month with very minimal loping/lunging and then it started doing it really bad again. We noticed that the plug from the firewall to the ECM was cracked (probably from the wreck) and was told that if moisture got in there it would short it out and cause the problem, replaced that and still not FIXED! Running out of ideas and money, husband going bald, wife going insane Please help!

 

LOL I wish

 

The last 5 times we have taken it to Cat they have kept it for about a week each time and every time the walk away scratching their heads saying I dunno. Ready to junk it.

 

we took it to a general diesel mechanic last week and he thinks it is the air to air box havent replaced it yet. Just mulling it over right now. We have taken it to 3 different CAT shops and the one diesel mechanic. Any and all suggestions are greatly appreciated. Does any one think that it has to do with the accident or just pure coincidence?