[bill]

I have a Sierra with a g16 b in it. , been running fine for the past 4000 kms since conversion , last night it had been idling for 15 mins or so , then it just stopped , it would Fire the fuel pumps but wouldn't start so I checked fuses , fuel pumps every thing was fine , this morning went to have a better look at the problem , hit the key and it fired straight up no problem ,took it for a drive for 20 mins , ran fine , got home went to sift it after it had sat for 5 mins and same problem again , check everything and found it to have a weak spark at the coil and no spark at the plug, fiddled around with dizzy and coil plugs for 1/2 hour and it fired up no worries , went for another drive running fine , any ideas what it could be seems to be when the engine is hot it has the problem my thoughts is a crook coil ,but strange once it is running there isn't a problem , got me stumped , any help would be appreciated .