Air, fuel or spark all at compression and the right time.
Since I'm not there and you are, you will be my eyes and ears and hands.
If this is too much for you then get someone with experience to help.
1- fuel do you have it all the time at the correct pressure, not a low tank, filter OK
2-Air- Is the air filter to the engine clean, not blocked, conduits clear, if you have idle air control is it plugged, PCV, EGR clear clean and not blocked.
3-Spark plugs all good, coil(s) wire HT leads connection all good
4-Do a compression check in all cylinders when hot with WOT, wide open throttle, it must all be within spec
5-Do a static timing check then a dynamic test to see if timing advances.
With all these done you can narrow down what's wrong, without it and since I am comfortable in my office I cannot touch your car, help me help you!