Spent $80 on a cheap borescope and it saved my whole weekend

I was chasing a misfire on a Ford Escape that had me stuck. The code pointed to cylinder 3, but the plug and coil looked fine. I bought a cheap borescope from the parts store, snaked it down the spark plug hole, and found a big chunk of carbon sitting on the valve. Took about 10 minutes to vacuum it out and the car ran perfect. What's the weirdest thing you've found with a scope?

2 comments

2 Comments

charlie_kelly1d ago

That "big chunk of carbon" story is a perfect example. It makes me wonder how many engines got new plugs, coils, or even injectors for a problem that was just a loose piece of junk in the cylinder. The weirdest thing I ever saw was a perfect, tiny pebble sitting on a piston. It must have gotten past the filter and through the intake somehow. It was just bouncing around in there, making a terrible noise. I fished it out and the knock was gone. It makes you realize how simple some scary problems can be.

patricia_hayes1d ago

My old shop had a rule. Always check compression first on a mystery misfire. I thought it was a waste of time. Then we had a Ford with a dead cylinder. Compression was fine. Pulled the plug and found a little piece of a broken valve stem seal just sitting there. It was blocking the spark. Took it out, car ran perfect. Changed how I see every weird engine noise now.