Thanks everybody. In the next couple of days I will check the wet compression and valve clearance. I did adjust the valves a couple of years ago. I’m only a kind of “intermediate youtube” mechanic and they may have come loose on me.
There is a bit more to the story… actually my car would not run at all without Engine Restorer. I neglected to add it after one oil change after using it religiously for years. Soon the car was throwing codes, but it was cylinder 1. I read only 40 PSI. But with Restorer it doubled, literally. I was amazed.
But, I don’t think that is the issue now as I top off both oil and Restorer.
I’d be fascinated to know why the engine does not throw codes in Drive but does on Neutral. The RPM stays about the same, hovering from 650 to 700. It takes a couple of minutes for the check engine to come on.
Also I see some fluid dripping from the exhaust, possibly coolant or gas or both. I couldn’t figure out what it was.
Interestingly, the car seems to run OK (but like ok4450 says, maybe I’m used to it) after it’s nice and warmed up and has driven for a while. It is at it’s worst if I drive it for a while, let it sit for half hour, then start it up. It really struggles then, but after 5 minutes or so, is OK.
Thanks everybody. I should really take it to a mechanic, but they just tell me to get rid of it. Actually 4 years ago a mechanic told me to get rid of it. Maybe this is it finally… I feel like I can keep it going a year or so if I tweak it a bit.