I have a weathermaker 8000 and lately we can smell ga...

I have a weathermaker 8000 and lately we can smell gas at the furnace. I have sprayed soapy water on all gas connections with no results. The smell is getting up into the bedrooms especially in the master which is furthest from the furnace. When I smelled around the furnace, the strongest smell was on the left top of the combustion chamber by the access door which can be removed. I am at a loss as to where the gas smell is coming from