Gas fumes

[Mr Jody]

With a Coyote motor I’m assuming fuel injection, thus electric fuel pump. I believe on most all fuel injected engines, when you turn the key to the “ON” position, the fuel pump will run to pressurize the fuel rails prior to starting,

For diagnosis, without starting the engine, turn the key to the “ON” position. This should turn the fuel pump on temporarily to pressurize the fuel rails. You can then look and smell for a leak in the engine bay (or anywhere you have fuel lines). You could even put a shop rag under where rubber hoses meet hard lines to help spot leaks. If you don’t see anything the first time, cycle the ignition switch off and back on to turn the pump on again. Note that you may have to wait a few seconds or even remove the key to allow the relays to reset and make the pump come on again when placed back in “ON”. Doing this with everything cold should slow evaporation and make the leak easier to find.

I had a similar leak on a passenger car where I had replaced a rubber fuel line where fuel enters one of the fuel rails, and I suppose over time, either the new hose shrank and/or the clamp loosened and a leak developed at this connection. Tightening the clamp stopped the leak.