I'm in Australia and own a locally made sedan which uses the 5.4L 3V engine.
I have a problem which is proving very difficult to troubleshoot. The engine will cut out when idling, very intermittently. Before it cuts out, the idle revs will usually waiver up and down. It happens more frequently when the weather is hot. The dealer has never been able to extract a single error code.
Ambient temp 29degC according to dash
There is a VHF 2-way radio permanently wired in to the vehicle, and that's what you can hear right at the beginning. It was turned off shortly afterwards, and the engine cut out while it was off.
Climate control was on
Standard radio was on I think, but turned down.
All other accesories/lights off.
Transmission in Park, feet off the pedals for the duration.
I have been searching these forums, and it appears that a comon cause of this problem is the IAC valve. Is it possible that mine is defective, even though no error codes are being produced?
The dealer can't find anything wrong. They have checked for leaks and run tests.
Is it a drive by wire or standard cable actuated throttle. Most times, the IAC will not throw a code. It's a good place to start. As for the pinging, it could be a timing issue in the PCM that may require a reflash, a lean condition from low fuel pressure or a vacuum leak, too much EGR flow leaning out the mixture, etc.