iPhone Connectivity to car via cable

For several years, I have plugged my iPhone 5 and now iPhone 7 (as of October 2016) into a cable to connected to the sound system of my 2007 Lexus without issue. (The Lexus offers Bluetooth phone but not Bluetooth music.) There is a 30-pin cable from the car stereo to which I have connected an Apple-made lightening to 30-pin adapter when I moved from the 5 to the 7. It continued to work perfectly with my new iPhone 7 for close to a year.

In the past several months, this connection has proved to be problematic. I have to plug and unplug my iPhone multiple times to get the music to play. I perform all sorts of gyrations, from switching the polarity of the lightening cable (turning it around), cutting the stereo on and off, starting and stopping the music, etc. It will eventually connect and work; it may take 2 or three tries and sometimes 10. I even replaced the lightening to 30-pin adaptor. It made no difference.

I have headphones that plug into the bottom port of my iPhone and they work just fine.

My daughter’s both have iPhone 7’s and they work much better in the Lexus, usually connecting on the first try. Even my wife’s iPhone 5 performs well!

At first, I wondered if it was an OS 11 issues, as I’ve had other problems related to the new operating system, but the fact that my family’s phones work tells me differently. What to make of this? Is there a way to test my port to see if the problem is there? Do I need to get Apple to replace my port? Can they even do that? (Obviously it's out of warranty.)

Thanks.