VN Calais 3.8 Backfiring After Coil Pack Changeover

Hi all,
Recently my VN Calais S1 has started to run like it was only firing on 3 or so cylinders (dont worry it has not left the shed). I replaced the coils with champion coils they cost me $58 each at repco. I also changed the spark plugs to the iridium/fusion ones cost me $140 at Supercheap and changed the leads to blue bosch high performance ones they cost me $80 also from supercheap. After $300 odd bucks it now backfires.
Checked and rechecked the OBD with the ALDL bridged, displays code 12 Operation is as normal. Checked and rechecked the spark plug lead order. Replaced the Module under the coils.

I should ad when i was driving the VN a couple weeks before this happened the idler pully (pathetic plastic one) bearings wore out and melted the pully as a result the belt slipped in towards the engine, due to being in traffic had no choice but to keep driving it to a open park. Would this affect the timing as the belt was slipping on some pulleys and not on others? and if so how do i go about rectifying the problem.

Any help would be much appreciated and Thanks In advance.

 

Hi,
I have been relying on the haynes manual the diagram shows the order is.
6[]5
4[]3
2[]1
(Radiator) Front Of Vehicle

and shows the coil pack as
6-3 2-5 4-1
Front of Vehicle

Is this correct as i cant find anything about the firing order in the Gregory's
and from what i have read online it seems to be different.
My ride is a VN Calais V6 1989 Series 1 with the Series 2 coil setup.

 

I understand where the cylinder numbers are but i dont get which spark plug lead goes to which of the 3x round coils as they are the aftermarket one's for series 2 they dont label them with numbers.

 

Thanks guys much appreciated.
Ill go have a look and see if i can find what is wrong

 

rob drag racer thanks for the pic, i realized when i was installing the coils that the DFI module under neath the coils has the numbers printed on it, of which cylinder spark plug lead goes to what coil.

I ended up swapping the DFI module back to my original one and it runs a lot better with no backfire.
Unfortunately now it has a slight hesitation when i accelerate, any ideas.

 

Thanks rob drag racer.
Whats the best way to go about cleaning the idle air control valve.
Gone!! me, no way, i need my daily JC fix. lol

 

Ill give it a go and see if it improves it.
rob drag racer hows your race status going.