To everyone,

Thank you for all of your kind help. Tom and several others were quite correct; the original poppet-style spider legs have a strong tendency to malfunction below 56 psi, and my friend admitted that it was below that at least half the time!

The twist to this story; he found a spec. in AllData that clearly said 55-62 psi KOEO, and that's just couple of psi higher than what he was seeing ... what a huge difference a couple of psi can make!

I found TSB 01-06-04-057, which updates the official GM No-Start trouble tree with the new values 60-66 psi, but it hadn't filtered through to the "Tune-Up and Performance Checks" Section of AllData.

The lesson to be learned ... always check TSBs before pretty much anything else!!

Thank you all!

Michael Barry
Technician
Quick Stop Smog & More
Sacramento, California, USA