If my tank is say, maybe half full when I go to fill up the tank the tank sucks in air when I take of the cap - is this normal?? I was thinking maybe it is the wrong filler cap. When I have a full tank the car is very jumpy when coasting - could this be the problem??
AHHA - maybe this could be the problem - the plastic arch that goes under the front wing is missing on the drivers side of my Cav so any dirt, water etc etc chucked up from the front wheel goes into the engine bay + drivers door. I was looking under the just out of interest and I saw this cannister - which had 2 leccy wires attatched to it - it also has a bit for a hose to go on to the bottom - but there is no hose connected - is there meant to be a hose here and does it go back to the fuel tank cos I checked everywhere aroung the cannister and could not find a hose to attatch to the cannister - could this be why my car runs funny when I fill the tank???
I had a similar problem on my GTE only thing was there was so much of a vacuum the tank started to crumple up. It turned out to be the vent pipe on the carbon canister that had got crushed inbetween the bodywork and engine cover (under the engine). Don't know if this is what is happening to you but it sounds similar. I never experience perforemance problems but it would take a massive gulp of air when the fuel cap was removed.