Genesis silver A not getting up to temp

Have a silver A that won't go much higher than 400 degrees. This was a flip that I never tested before disassembling, cleaning out the burners (which were in good shape), and reassembling. Before I try swapping out regulators, manifolds, or burners, any suggestions on what might keep it from getting any hotter?

Thanks in advance!

That is a telltale sign of a bad regulator and is a 2 minute repair. I'd try that first.

Yep my $$$ on a regulator

Or you have the vapor lock going on. Try turning off the tank, the burner knobs and then disconnecting the hose from the tank. Wait a minute and reconnect the tank. Then open the tank valve really slowly until it is about half open and continue to fully open it. Then turn on the first burner and light it, then the other two burners. See if that helps before you start replacing parts. But, yah, the regulator would probably be my next step.