"It's a novel idea but the scope isn't going to give you any more ideas than
a good set of ears and eyes will. "

One thing a hillbilly taught me was if you have a miss and want to know which cylinder it is to put your hand on or near the exhaust manifold (depending on how long it ran) and one part of it will be cooler than the rest.

Another backyard mechanic taught me about timing chains. Take off a valve cover ad see how far backwards you have to turn the crank (with a wrench) to get the valves to move, more than a certain amount the needs timing irons.

The olman taught me that when an engine jumps time the cam is almost always late in phase which will give you higher measured compression but low vacuum. However that has changed because almost all cars use a tensioner. Some of them jump at shutdown and could be advanced instead. Sometimes it is the tensioner that goes bad.

The buddy who taught me about the timing chain trick actually brought a car to me after it had been to Mr Goodwrench and they said "Replace the engine". It was down to cam timing or the crank sensor which was terribly hard to replace in that model. It was running like **** and pretty much couldn't get out of its own way.

I looked at it and drove it and did not know much, just that it ran like ****. Eventually I removed the cover from the throttle body to see if it was getting a good stream of fuel. Well it was but when I tried to rev it up it spouted gas right out. I said "Tear down for timing chain". He said Mr Goodwrench said there is no timing chain, this old 151-4 has gears. The next day he shows up at my house with a broken timing chain tensioner.

Think Mr Goodwrench would give him back the fifty bucks they charged to misdiagnose the thing ? Hell no.

In my business you had hell to pay for a misdiagnosis. apparently the ASE certification males you like a doctor, you get paid even if the patient dies.. Buncha **** IMO.