I have a luxaire high efficiency furnace that will not stay ignited on wet or very damp days. It will ignite and burn for around 5 seconds and turn off. The blower runs and it will ignite again only to repeat the cycle. Does this sound familiar to anyone?

Is it all the time cause if so your flame sencor might be dirty or have some trash in the burner ***.

No only on rainy days. The ignitor has been replaced and the unit has been cleaned. Also we have used a blow dryer to force air into the venturi tubes and the unit will stay lit until it has reached the temp setting and then will repeat the cycle. We did this thinking there may be moisture issues.

Also have had a new flame sensor installed