1998 Chevrolet Blazer rough idle

I think the timing is alright, we made sure we had the mark on the gear line up with the mark on the engine, it might have been a quarter of an inch off but not much, we got a new pcm for it, they said it was already programmed, but we took the chip out of the original one and put it in the new one, I dont really know if that matters or not. My Dad seems to think its the PCM computer but I have my doubts, he knows more about this stuff than I do. It could be the PCM computer

Well my dad said the timing was alright and I made sure that what he said was the truth, so I just go on and believed what he said was true you know, the computer is new, but we ordered another one and we are going to take it to Ed Martins and have the program it, they said its already embedded with a chip if this other one doesnt work, hes gonna take the chip out of the new one which is the original chip for the first computer, we are just taking that chip out and putting it in the new one, but like I was saying I dont know if the chip has anything to do with it, my dad told me that it has nothing to do with the engine itself but he said the timing was lined up correctly