So here goes, I just finished swapping my 4.6. At first start up, I had code 357 which was caused by ground wire to #7 cop being broken so I ran a new wire from pcm to coil and the issue was fixed, only to be replaced by codes 352 and 1504. Which are iat sensor malfunction and #2 cylinder caused by the same as the #7 issue i just solved. I'm just wondering if anyone has any insight into why im getting new issues after fixing the previous ones, this is starting to get very frustrating. Any help would be greatly appreciated, thanks

 

Well you have only had three codes two of which you already solved..fix the third and that may be the end game. Anytime you swap an engine its not uncommon to have to tweek a few things. You have to watch with miss fires because many times you fix the coil or whatever and now you have fouled sparkplug which was caused by the coil issue for example. Stay with it until you have no codes and then enjoy the new engine. Not all that unusual.

 

Thanks for the input, I forgot to mention the two weeks prior of trouble shooting to get it started. It just seems odd that my harness has gone bad now in three spots, from the pcm to crank sensor which I fixed to get it running, then from pcm to #7 coil and now from pcm to #2 coil, All of which was fine before the swap and the harness was removed while all the work was done.

 

Just curious if anyone has ever experienced their harness failing repetitively like this

 

Well to solve a problem you have to first identify that problem. If the harness wires are developing breaks in them then find out what is causing the break, mice, squirrels, chewing on them etc. and apply that information to the other areas of concern. Sounds crazy but happens sometimes with a vehicle that sits in a barn or garage for awhile unused..this is just an example but you see where I'm going with this. Is the harness damaged by battery acid and the insulation is being compromised? If I replace a wire and now things work then I suspect the wire or harness or the connections. Check the main pin connections for corrosion or tightness. Bottom line is find and identify the cause of problem then make the changes to solve it. I know you want us to just tell you what the problem is,wish I could but that is not possible at least for me.