[a.c.ward]

with manifolds dont sound like vapor lock. sounds more like a clog in the fuel system. agree with getting a clear filter and verifying fuel flow. with the idle dropping when engaging drive, you should maybe look at increasing your idle rpm to 750-800, when in neutral, and 600-650 in gear.

keep us updated, there are many great guys on this site who are more than willing to share thoughts, ideas, and assist in troubleshooting.

the best site that I have come across, many good folk on here.

AC

still in Afghanistan