Boy, does my son's slant run crappy!

I'm going to do some additional troubleshooting and I'll let you guys know what's going on. I appreciate all the suggestions - gives me more things to double-check or confirm.

So far...

No EGR
No overheating
No backfiring
Not sure about unusual smell - I don't know what it normally smells like
New rotor and cap
Tried new ECU - had no effect (is grounded properly)
Choke closed when cool - open when hot
Carb is bolted down tight
All vacuum lines are intact

I'll be back.....