Hey guys my truck is turning over but won't start. The motor is an l20b with a weber 32/36 and electronic distributor, I think it's a spark issue. I ruled out the fuel pump and fuel filter, I ran the outlet fuel hose from the fuel pump into a bucket and when I cranked the motor it squirted plenty of fuel. The carb also seems to be feeding fuel as it should, I see fuel as I throttle. I checked for moisture under my distributor cap, didn't see any condensation at all. Swapped new spark plugs in. I had it running once, I used some carb cleaner and it coughed for a bit but after a minute it seemed to be running ok, then I let off the gas to see if it would idle, and it cut out. I did notice my vacuum advance was loose, the screw was lost somehow, I used another screw to temporarily tighten it, it's still a little loose, I'm not sure how big of an effect this would have. I'm not sure what the next step is so any advice would be much appreciated, thanks in advance.