Still sounds like it's only running on two cylinders
Confirm its still cylinder 1 and 2, by starting the car with each plug disconnect and see which ones make it worse
Originally 1and 2 made little difference, but 3 and 4 made a lot
If this is still the case, 3 and 4 are running fine, no amount of changing sensor throttle bodies and so on will make any difference, all 4 cylinders would be acting the same
Ignition leads, injectors, inlet manifold, head gasket exhaust, plugs would be about the only things that can effect two cylinders only
Seeing it happened straight after an overheat, the odds are inlet manifold or head gasket
The car was running fine before the overheat, the leads must have been in the correct order. There's no need change the order
Take the 4 new plugs out keep them in the correct order and take a nice closeup of the electrode end
You say you have bubbles entering the radiator, is this a steady stream of bubbles or an occasional one
Confirm its still cylinder 1 and 2, by starting the car with each plug disconnect and see which ones make it worse
Originally 1and 2 made little difference, but 3 and 4 made a lot
If this is still the case, 3 and 4 are running fine, no amount of changing sensor throttle bodies and so on will make any difference, all 4 cylinders would be acting the same
Ignition leads, injectors, inlet manifold, head gasket exhaust, plugs would be about the only things that can effect two cylinders only
Seeing it happened straight after an overheat, the odds are inlet manifold or head gasket
The car was running fine before the overheat, the leads must have been in the correct order. There's no need change the order
Take the 4 new plugs out keep them in the correct order and take a nice closeup of the electrode end
You say you have bubbles entering the radiator, is this a steady stream of bubbles or an occasional one