Treaded valve ????

I have a 1999 Opel Astra G 1.6 16v. The water pump broke at only 30,000 km, and the timing belt jumped. After installing new pumps and timing belts, the engine won't idle and runs like it's only on three cylinders. I'd like to know if this is due to a stuck valve and how to be sure, or if it could be something else.

Hi...put the misfiring piston in the compression position (valves closed, piston at top dead center). It must be exactly at top dead center. Inject air through the spark plug hole, and no air should escape through the muffler or exhaust or the intake. Say a prayer and you're done

I am comprehensive, salts of doubt immediately, if there are valves footwear it will be a brand of 0 or very little precion, it passes a lot with today's vehicles jump teeth and bend valves.