Lincoln Repair Questions? Ask a Mechanic for Answers ASAP
Hello and welcome to Just Answer. My name is James.
So, there's a few things going on with your Navigator based on the codes you listed. Are you having ABS trouble? Is the engine running rough? Did you bring it to the mechanic just to have the light diagnosed?
Ok, the P0303 indicates a misfire on cylinder #3. Have you had spark plugs replaced recently?
With an air rushing type noise, it's likely that the spark plugs has loosened up and you're hearing compression pressure leaking past the spark plug threads and causing a misfire. You're 5.4 3 valve is susceptible to this after spark plug replacement due to carbon dust collecting on the spark plug threads in the cylinder heads. When plugs are replaced, the spark plug bores need to be blown out with compressed air to clean the threads, and the plugs need to be hand torqued to 25 lb/ft.