97 GMC Monday Startup Problems

97 GMC Sierra 1500 with 5.0L and 180,000 miles.

For the last several weeks my pickup has had a hard time starting on Monday morning. It seems related to whether I start it every day or not, because I some times don't drive it on the weekend.
It cranks over fast, not acting like a low battery. For the first 10 seconds of cranking it doesnt seem to fire. It then seems to act like it fires a couple of times then will act like it is misfiring enough that it stalls out the cranking. It may take 30-40 seconds of this funny cranking with mis-firing and near starting before it starts. It starts rough for the first 5 seconds or so then runs great and starts and runs fine all week.
BTW a normal start on this is just a 2-3 second turn over so something is clearly different after it has sat for a while.
I am wondering if I have a computer/electronic ignition problem but seems odd that I am not seeing any other bad effects.