Throttle Jerky At Low Revs ?

[Falcon 269]

Sticking EXUP would give tacho error code.  If it's maladjusted, it would have been that way before the winter lay-up.

I'm thinking stale fuel and carb blockages.  However, overhaul the EXUP anyway and if that doesn't cure the problem, try some Redline carb cleaner (search on ebay) to see if that will save you a trip into the carbs.