Heres the problem. The engine fires up ok. When any throttle is used, it coughs splutters and backfires.
Its a 2.0L sohc pinto engine that ran well when i got it over 2 years ago but has been stood since (although turned over regularly)

Hers the facts:

I have a good spark on all 4 plugs
I have new HT leads and plugs
I have fuel in all 4 pots.
I have the same compression in all four pots (give or take the odd psi)

With the engine running, if i remove a plug lead from No1 cyl, the engine dies
With the engine running, if i remove a plug lead from No2 cyl, the engine dies
With the engine running, if i remove a plug lead from N03 cyl, the engine carries on as normal
With the engine running, if i remove a plug lead from N04 cyl, the engine carries on as normal.

Am i missing something obvious

The psi is about 160 for info.
I can't think that changing the dizzy cap will change anything as i have a spark at the plug anyway.

I have just ran out of ideas now :(

Okay, start laughing at me now B) ,

Talk about couldn't see the wood for the trees.
I was so engrossed in the less obvious bits, i didn't check the obvious. I had plug leads 3 and 4 switched.

All sorted now and the mot is at 2pm. Off for a quick lunch and a run in the sun to the garage :D