I went to use my millermatic 252 today and did the usual, turned the c25 gas on really slow and then after the high pressure needle increased to its max, then opened the valve all the way.

i always back out the regulator screw when finished for the day, I assume it is better to leave them this way when not being used for a few weeks.
This time I noticed when increasing the screw tension the low pressure side didn't increase as usual like it was stuck and then it jumped up higher than I wanted, so I backed out the regulator screw a bit and then pulled the mig trigger to set the pressure in the range I wanted.

The problem is the regulator needle is bouncing all over the place when I pull the mig trigger and i hear like a ding..ding..ding..ding..ding sound constantly coming from the regulator when I pull the mig trigger. I feel gas coming out the mig gun, but don't know why the regulator is making this sound or why the needle is jumping around.

i get the same response from the regulator if I loosen the hose at the low pressure output side of the regulator and bleed it out to see if will maintain the fixed output pressure.

anyone know what could be wrong? I'm pretty frustrated by this seeing this would have been my second chance to use the new welder.