timing chain question

[one]

My 88 k5 is causing me some serious headaches...It has been flashing a code 42(est. circuit), stalling and idling rough. I have since replaced the complete est. circuit, including wires, ign. module, dist. and ecm...to no avail...my question now is could the timing chain effect the dis. signal to ecm if there is too much slack and has skipped a cog? Has anybody heard of this happening? I'm thinking this could be it because when it stalls sometimes it won't set the code...
Thanks for any input.