Replaced battery and starter ,98 firebird 3.8, dash lights up full power, turn key to crank, nothing, security light is blinking. rotated engine. not sure about the problem.

Make sure your key is clean and you may have to replace your key Try that first may be your body control module?

Found out it is the ignition module, if I buy a new one with keys does it have to be coded to the computer.

Depends on the year of your vehicle but most likely you're going to have to go ahead and replace the ignition module and the keys I'm pretty sure you have to do that. It's more secure that way you don't have to worry as much about people stealing your car that's why they do it like that.

I would call a GM dealer to make sure but I'm pretty sure you're going to have to go ahead and get your key coded to the car's computer but sometimes you just have to turn the key a certain amount of times and it learns the new ignition module but check with your dealership I'm not sure?

I found out the problem was the wire coming from the ignition was broken, I took the steering apart and pulled the ignition, then a new one would have to be recoded, I chose to repair it, I used small speaker wire about the same size, S I soldered it and heat shrinked it, worked like a charm.

By the good graces of the backyard mechanic that's the way to do it you would have given the dealer $1,000 to do it!!! Good job!

I have another problem, the car set for a few years, when it cranked up it ran real rough, no power, so I replaced the plugs, that was a chore, it improved a little, still sounded like it was misfiring, I replaced the ignition coils and it improved, still runs rough, checked pvc valvle very nasty, also I was thinking of the mass air module.

Yeah it might just be that you have old gas in there too you might want to siphon the gas out and put some new gas in if that won't work then might have to take the gas tank down and clean it out but hopefully won't have to do that? Also you should clean the mass airflow sensor you know you have to buy special cleaner for that you can't just use anything on the mass airflow sensor and then clean the throttle body too I sprayed seafoam into mine while the car was running I would try those things before I would take the gas tank out but of course please take all this as an armchair mechanic here I'm not there with the vehicle you know better than me. Also check YouTube on stuff you need to do it's a big help!