3 liter CIS engine fumbles, stumbles at start up and...
 

... I can keep it running with more gas. It feels like 2 cylinders are not playing with the rest.

This has happened about 3 times recently - and the "remedy" so far has been to get the rpm up to about 5500 (on the road under load) and then the rest of the engine comes back to life.

Directionally - does this sound like electrical, fuel or some other related?

So what year engine? 3.0s ran from 1975 or 6 (Euros) through 1983. Various changes along the way.

Pull some spark plugs - are they black (too rich on start-up maybe) or white (too lean running).

Sounds like CIS related.

Hi Walt,

It's a '76 Euro 3.0 with '78 sized CIS and 'slightly' enlarged throttle body. Also - it really oscillates on cold start up between 500-1700ish for about 45 seconds... WUR related I suppose.

I'll check the plugs tomorrow - thanks,

Vacuum leaks will cause the oscillation as well.