I stumbled across this solution almost by accident. I was working in customer service in a carburetor shop some years ago, and the shop's policy was that "we did not work on cars". The customers were required to arrange removal of their carburetors and just bring that single item in for us to test and repair.
The issues arose when a customer would drive back to our shop in the pertinent vehicle with a complaint about our technicians work. Our shop's warranty required him to arrange removal of the carburetor elsewhere and bring it back to us to test again. Some customers did this several times before losing their tempers and calling us every name in the book. Now our technicians KNEW their jobs and knew exactly what they were doing. So they also KNEW the odds were that there was no actual problem with the carburetor that they had repaired.
Unfortunately, they also knew that they were not personally going to have to deal with the angry customer the third time he came back, red-faced and swearing! That was the job of us customer service people!
Finally, this had happened once too often, and as one customer angrily scowled and said "you mean you won't even come out and LOOK at my automobile?" I sighed and said "OK, I'll take a look!"
He opened his hood and I watched as he started his engine. Sure enough, it did exactly as he'd said it did, even though our techs had said "that's impossible!".
I went in and described to our techs what I'd just observed. One of them said "Well, we KNOW his carburetor is all right, he's probably got some bad electrical connections, he needs to clean his electrical contacts."
"How would he do that?" I asked.
"Easy" replied our technician as he handed me a can of spray electrical contact cleaner. "Just use that"
So I undid his carburetor's electrical connectors and sprayed them liberally with a shot from the can, waited a few minutes for the connectors to dry and reconnected them.
Presto! His issues had disappeared, and a few minutes later so did this previously unhappy customer, automobile now running like a top as he drove happily away..
After that, I made sure I got a can of electrical contact cleaner myself from my neighborhood auto parts store and have often used it over the years to cure many of my own automotive ills. And this is an especially handy item to have with the newer cars now, as there is so much more to their wiring harnesses than the older cars ever had, and the more there is, there more there is to go wrong with them.
So, the next time you think your car's wiring system may have "gremlins", turn off the engine and disconnect your electrical connections one at a time and give each a cleansing shot (use ONLY an automotive electrical contact cleaner, not any sort of brake spray or carburetor cleaner etc. or you could damage your wiring and connnectors). You might be amazed at how much better your vehicle operates! And you might be able to avoid a trip to that $150 an hour specialized automotive electrical repair shop.
