Chevrolet Repair: 1988 Corsica still not starting, haynes repair manual, spark plug wires

Question
Mark.....  My 1988 Corsica  V6 2.8L  still doesn't start.  I have replaced the fuel pump (new), pressure regulator, all 6 injectors, ignition module, timing chain & camshaft gear, good used ECM......It still acts like it is out of time,  yet I have set the timing exactly as shown in my Haynes repair manual. The timing chain is not loose, and All marks line up. Timing light shows firing right on the mark. I have not reinstalled the alternator nor anti-freeze yet,  as I don't believe those items would stop it from starting. (It did keep running once when I lost anti-freeze,  and once when the alternator went bad.)  Also made sure plug wires were plugged in correct coil modules as shown in Haynes manual. ( they don't go 1-2-3-4-5-6 straight down the module according to the Haynes manual) I can't think of anything I have overlooked,  and am about ready to tow it to a reputable garage for diagnosis. Is there something about the timing I need to know that I might be unaware of with Corsica's ?  It still acts like out of time...eg: coughing and backfiring. More so since I installed a different ignition module. ( That was kinda tough to install)  This is the same Corsica from a few weeks ago  that wouldn't start. I'm a pretty good mechanic myself,  but this has me buffaloed.  Thanks ! again !

Answer
Hi Dwayne, The only thing that I can think of is the spark plug wires are on wrong. Number one is in the back of the engine and number two in the front side. There should be a diagram on the under side on the hood or strut tower that shows the ignition coils and which number cylinder the coils are for. From memory I think the coils are from passenger side to driver side...5-2,6-3,1-4.

There isn't anything that should stop it from running.

Mark