Hello,
For a long time I've had spotty black deposits around the gas filler area of my truck. The deposits are all over the inside and near the outside of the fuel filler door and around the outside of the filler neck and gas cap.
They are hard to remove with simple detergents without scrubbing.
I have a 2001 Ram 1500 with a 3.9L engine, and use regular ( 87 octane ) gasoline. The deposits are pretty easy to see with my white painted truck body.
Any ideas what causes these deposits, and the best way to remove them and keep them off?
Thanks in advance for your input(s).

 

If you could get us a few pictures of the affected area, then I'm sure it would really help us see what the problem might be.

 

almost sounds like fuses are coming back up through your filler neck.

has anyone ever siphoned gas from your truck? if so they probably popped the orange "ping pong" ball into the tank. this ball moves down the filler neck when you put gas in the tank and moves back up to seal the tank. the gas cap is just to vent the fumes

 

it is due to the ethanol in today's fuel, might get some relief from a new gas cap as I don't believe it should be venting. and I open my fuel door and wash in there when I wash the entire truck.