Much of the time, engine and chassis problems can be diagnosed with either shadetree wisdom or a professional engine scanner.
Recently during a visit to Desolate Motorsports, I learned about a problem that defied every diagnosis.
A customer brought in a Jeep J-10 he'd been working on for a while. It had been treated to a number of custom touches, including a one-off double cab built by splicing two cabs into one. The sheet metal work is no hack job--it looks like something that rolled off of a super-secret black ops assembly line.
Instead of the stock engine, a Chevy 383 was swapped in. The 383 wasn't running well, and the customer wasn't having any luck tuning it.
Desolate started out by checking the normal stuff like timing, spark plug wires, distributor cap, etc. Nothing was obviously wrong, yet the engine refused to run right.
After eliminating several possible culprits, they pulled the camshaft and took a closer look. Although the lobes were in fine shape and the distributor drive gear looked good, there was still a problem. The distributor drive gear needs to have 13 teeth. This one had 14! As a result, the distributor was constantly out-pacing the engine.
How did this happen? Did a CNC technician push a wrong button during programming?
This goes to show that even in our high-tech day and age, wierd stuff can still happen inside your rig.