[DannoXYZ]

I doubt intake vacuum-leaks would be severe enough to cause no-start condition though. Would also cause problem with cold-starts as well if it was that large. More likely it would only cause unstable idling warm or cold.

1. I suspect petcock or its vacuum supply. Need to measure things to rule that out.

2. Also have you tried starting with gas-cap open? Cap vent-mod isn't removing screw, but entirely removing one-way valves inside gas-cap.

3. Test for spark as well when you have hot-start issue.