I usually get a kick out of someone who comes to a forum covering late 90s to early 2000s vehicles what are not running right, looking for help.
By the time they get to the forum, they've already spent $600 to $1,000 trying to fix it with a screwdriver and a monkey wrench, changing parts. Try this, try that, hope for this, hope for that.
I just read one such post where a "scientist" who owns a 97 Chevrolet truck is chasing a high idle condition. After guaranteeing an annual bonus to the local parts supplier, same problem. Of course, taking it somewhere for a diagnosis is "too expensive".
A high idle on a computer controlled engine is almost always a result of an air leak along the intake system. The engine takes in more air than the computer is "allowing" and to compensate for an overly lean mixture, more fuel is added, thus, the higher idle.
By plugging in a scan tool that will read data, you can usually see the fuel trims pegged out to the max which indicates an intake air leak. But, George and Elmer run back and forth to the parts store until they run out of money. Then, cry for help.
I laugh at them.
