ansaari

There isnt any valve in the fuel tank at all, Fuel neck is directly opening to fuel tank. Leave the petrol cap open for about few minutes ad then start the car and again open the cap n refill. If this doesn't help then you need to open the fuel tank and see whats blocking in.

Check the spark plugs, air filter, ignition coil and engine oil hasnt turned black?

Either case i suggest don't drive car and just remove the whole engine oil and filter and verify that you find that piece. If you dont then seek a mechanic to open the sump and trace it so that it doesn't reach to crank or engine head.

Check some fuse must be blown or some relay must not be working in breaking the contact while car is off. More doubt is on relay.

i have got my Q7 2008 tiers inflated with nitogen when the beeping started thatthe tier presurre was low but it still had oxygen so i slightly mixed it the beeping still cont. is it OK to mix oxygen and nitrogen? And also how can i stop the beeping when my car