Gas dryer slow to light up

I have a 17 year old gas dryer from Amana, LG4609W. Recently it is taking longer to light up. The igniter works right away but the gas does NOT kick in for a long time (20 seconds). Use to light up in less than 10 seconds. the dryer still works but seems to take longer to dry clothes. I realize there are 3 potential parts issues - igniter, flame sensor, gas valve control coils. Which is the likely culprit?

Based on reading several posts here, I decided to replace the valve coils. Hardest part was getting the plastic connectors off the old coil’s pins. Relatively easy otherwise. Still slow to light up but it is working. perhaps the ignitor is taking longer to reach the cut-in temperature? Not sure…

The ignitor is getting weak, that is why it is taking a long time for the flame to come out. Tom ApplianceEducator.com

[QUOTE=kayakcrzy;313619]The ignitor is getting weak, that is why it is taking a long time for the flame to come out. Tom ********************************************[/QUOTE]
Replaced ignitor last week. Still takes 12-15 seconds for flame to ignite after ignitor starts to glow. Is it coils, ignitor (again), radiant sensor? Not sure where to turn…