I was thinking vacuum line to the cool fuel if your running that

I have a throttle body if you need one.
Just letting you know.

FIXED !!!!

Bup got me thinking about whether the throttle blades were closed or in the right position. Checked the good running motor (had this blower gone thru also to be safe) and the throttle blades were both closed. Evidently when we had the motors dyno'ed this blower still needed some throttle plate opening to run right. So I set both blades to be closed and holy crap, it idles as smooth as can be at 800 rpm. Evidently this blower had been weak for some time.

Thanks guy for all of your suggestions. Sometimes it is right in front of you, but you still miss it.

im glad you got it figured out.i knew you would.