Random misfire

Code P0300 Rodded cat.

Has timing chain, not belt. No has never been changed.

Random missfire at idle. P0300. No cylinder missfire code. No other code. Engine compression 120psi on all 4 cylinders. Spark plugs clean. Engine vacuum low but not swing wildly. No vacuum leaks. Small intake manifold easy to check vacuum leaks. Ignition timing dance between -5 to +15 at idle. When the engine rav to 1600 rpm every thing back to normal. Smooth no missing.I changed, swaped or disconnected every sensor and computer with no luck. Could the engine has mechanical problem but still have good compression? I also put gas treatment in the tank in case there has water. I filled tank 2 times after I burn up all the gas. Thanks

I don't know how to check that since I don't have anything can do that at my disposal. I only have a Autel AL619 OBD live data scanner. I put a new coil pack, new wires and new spark plugs at early stage. Since this is a 2005 so OBD self diagnostic is not that sensitive as cars made in recent years.I never got a single cylinder missing code. What could cause ignition system not produce sparks at idle speed? The spark plugs very clean and not have any black color at all. Thanks for help.

I can tell if there has any miss by put my hand at exhaust pipe. I feel those pulse at idle but there has not even been a single one at 1600 rpm. There seems has a gap between 900rpm and 1600rpm. Even a slightly movement on throttle which I put 2 layer of printing papers on the throttle stop screw.I can't turn that screw because they put some locktight. This is a used throttle I bought from ebay but it actting same as my old one so I don't know if both of them are bad. This car use waste spark ignition coil pack so if the coil has problem would cause two cylinders miss and stall the engine but my engine never stalled. I have new NGK wires and spark plugs.
The slowest idle I can achieve is 1600rpm by sticking paper between stoper and lever. The idle will goes to 2200rpm if I stepped on the gas padal. Do you think this could be a bad throttle?

It'2004 aveo 1.6liter Throwing codes p0700 transmission control system, p0300 random misfire detected, p1781 engine torque signal circuit. Car randomly dies driving on the hiway, pull over, stop restart car goes again any answers? My local chevy dealer tells me thier is nothing wrong! Please help

Thank you for point out the possibility two posts per coil and only one spark. I tried before using timing gun and I did find out that one spark plug wire has stronger light than another wire even they came from same coil and both coil have similar results. How could it be? I am really baffled. I changed a new coil but no improvement from old one. I also changed a used computer and also is same. No vacuum leaks and long term fuel trim always negative around 15%. I am really appreciated your help. Can you tell me why this 2 post from same coil could have different voltage?

I have changed the plugs and wires on my aveo, and there was oil around the spark plugs. So, I put on a new valve cover gasket with the gromets, and that solved the oil problem. But, it is still random misfiring. What else could be the problem?