I have a 2000 dodge durango 4.7 that I cannot find out how to fix. Let's start with some back ground on the truck. I just got it a week ago. I bought it after anothee guy replaced a cracked head.on the passenger side. The truck after being assembled then spun the cam dowel after being started the first time and ran for a little while. He said he overtightened the cam. He then took the cam off the old head and put it onto the new/used head and fixed it but since he had no idea where the timing was at when assembled. I took the valve cover off both sides and reset the time back to zero on everything. I got the truck started and it ran rough and wouldn't idle. I can getitto revup and oncepast 2000 rpms it runs great. After the first start up it threw a code for ignition coil 1 and 6 being out I replaced those two and then it threw a code fo 3 and 5 ignition coils being out not wanting.to throw more money at it I did a lot of research and came to the conclusion that it could be the idle air control so I replaced that. Now it is throwing codes for coils 2-8 being out. I am so lost now on what it could be that is making this truck.run so bad. I cannot get.it to idle I can get it to.run ok after 2000 rpms. Please help.

As of today I replaced the throttle position sensor and it still won't.idle