Weird problem I'm having with my 95 trans am, it will start and idle rough for about 4-5 seconds then die. Scanned it and got codes 16, 42, 41, 36, 46, 18, 51. Swapped in a buddies PCM and now it runs but still rough but at least I can drive it around. Scanned it again with the different PCM and got codes 46, 18, 51. What gives? Could this be caused by a bad opti? Everyone I've talked to says it's never the PCM. What should I look for next?
16-low resolution pulse failure
18-crank signal open or no signal
36-high resolution pulse failure
41-EST open
42-EST grounded
46-Vats fuel enable problem
51-ECM prom error
(for diagnosing I'm using a snap-on MT2500, and MT2400 but still learning to use them)

 

i would say try someone elsess PCM and see if that works