I have an el falcon that is missing badly when idling but it will rev ok without any problem. If it is neutral and I rev it at 1800 rpm there is a slight vibration. It shakes a little when it gets under load around 1800 rpm going up a hill but when the auto kick down to a lower gear it revs ok and goes well. The idle is very stable on 750 rpm but there is a constant missfire. pop pop pop out the exhaust and engine shaking.
I have checked compression, leads, cap, coil resistance, fuel injector resistance, tightened inlet manifold bolts, cleaned throttle body, change plugs. All plugs look like firing clean, not rich or lean.

Has anyone seen this before? Thanks for any reply.