Jenn Air gas oven won't light
 

My Gas oven will not light without some help. We pull it out and tap for a while on the regulator and then gas flows and the ignition proceeds apparently as normal. It will then cycle on and off while baking. Is there a test process to figure out if it is just the regulator that needs replacing? The oven valve is adjacent to the regulator so we could be shaking that a bit when we tap on the regulator. Visually the ignitor seems OK.

Thanks