gas dryer not lighting properly/ every time

[lhenman]

I’m guessing this unit is over 10 yrs-it was left in the house 6 yrs ago. I ran the dryer Saturday 4 cycles in a row. Each time cold wet clothes- the drum is turning etc. No heat. The ignitor glows when turned on. I fiddled with it turning it on and off several times and it will light eventually and it will run the cycle with heat i found after playing with it. For three days I have done this trick until I hear the gas ignite- but obviously there is something going wrong. The.best I can tell.it would be the gas valve coils but needless to say I have never worked on a dryer before. I got the replacement part but being non returnable after opening I was hesitant to replace because three repair shops thought it was odd I could get it to light after trying it a few times. Before I waste a 50.00 part I thought I would ask for suggestions. I read this part can gradually go bad so is that possible that its hit or miss until it finally blows completely or is it something else?