[SOLVED] Cylinder 1 Misfire - P0301 / P0300 Mystery

[Skyline]

Originally Posted by Toothbrush

Second/new gauge + leak down test is the next 'to-do'. I'll post those results (maybe early next week) once done.

Yep, I didn't wait very long to do the valve seals once the smoke started (maybe a couple of weeks, after heavy research). No lights up to that point, and a couple of codes that I fixed. One for coolant, which was a rotted fitting for the upper radiator hose and one caused by a bad seal or crack in the crankcase vent hose (replaced same day). No other codes or Lights.

The cheap boroscope I have stopped working, so need to pick another one up. Went to use it while I had the valve cover off and no picture. I know for sure the top of the piston is covered.

I've been looking at the kit you suggested and am 95% sure I'm going that route before anything else. I've keep hoping it's a sludge/carbon issue that just needs to get cleaned up.

As far as the boroscope, I've been seeing a lot of ads for one that hooks to a smartphone. Looks very promising and quite a good deal. But if you can get your hands on a really good one, (like the Snap-on unit); that's better. I know some of the more recent high end models have an optional head for the probe that can look up and in different directions. You're not really interested in a view of the piston; you want a close look at how the valve is seated.

As far as the decarbonizer set up, where are you located? Close enough to borrow mine?