disturbed distributor

97 chevy c1500 4.3 l vortec

Ok, I have read all the manuals on how to reset a distributor that is disturbed. I turned the motor to tdc on the compression stroke. Aligned the marks on the crank pulley to the marker on the timing cover. Turned the oil pump to align it with the distributor. the rotor segment is setting very close to the "6" marked on the base of the distributor. Checked all the plug wires. It still backfires through the intake. If the distributor is off one tooth will it cause this? Does the rotor segment have to be dead on the "6" mark? By the way the timing on this engine is controlled by the computer. Did check all the plugs to the crank and distributor. Is there something that I am simply missing or not understanding? Any help would be greatly appreciated. Thank You.

There are two marks on the damper, provided you're using the correct one, your procedure is spot on perfect.

http://i561.photobucket.com/albums/ss58/cwhook/Distributorrotoralignment43L.jpg

If the distributor is off only one tooth in either direction, it's unlikely it will backfire. If it's set to TDC of the exhaust stroke however, it will most certainly backfire. Try dropping the distributor in 180 degrees from where you have it. Post your results.

thank you i will.

i got it to run. I had put a new head gasket in and one cylinder rockers were not in correctly. It runs rough now and I am either figuring I am out one tooth. It may also be that I just had it really flooded and it needs to run to clear out the plugs. I blew a power steering hose so it will have to wait till I run into town.