gas dryer flame not staying lit

Hello. My dryer flame will not stay lit over 5 seconds. I have tested flame sensor for continunity and it is OK. I replaced thermal fuse and that tests out fine. I have tested the cycling thermostat and that is fine. I replaced the coils with new ones. Finally I have checked for blockage in air flow and tried disconnecting the vent in back. Nothing seems to work and I am stuck. The flame seems to be large and not well formed (if that makes sense) meaning it touched the thermal fuse at the top. It never really gets blue or steady. I can’t think of what else to try because many posts all indicate the coils or igniter or fuses or air restrictions. Please help me I am sick of hanging socks in the basement! Also, once flame goes out the ignighter comes back on in a few seconds and the flame lights again only to go out and repeat the cycle.