I doubt the engine runs smooth if 2 of the 4 cylinders are misfiring. Maybe they don't at all times though. Sound on a recording are almost impossible to diagnose. One has to be there listening to it to understand the sound. Something sounds bad on it - could be a rod bearing or two rod bearings. I don't think it is coming from the head, but if the cam clearance is excessive, that could be the problem. Usually cam clearance gets tighter with age though, so the absence of any sound would be concerning. No problem with oil pressure light coming on after the engine has put some miles on the highway and then driven off the highway and parked & idling for a bit?

 

Sound like you have an exhaust leak among other things. Fix the leak so you can hear the other issues more clearly.

 

Have a look at the scissor gear on one of the camshafts. Maybe the spring that eliminates backlash has lost it's tension and allowing the gear teeth to chatter. That might explain why the noise goes away when you rev it up.

 

Sound like you have an exhaust leak among other things. Fix the leak so you can hear the other issues more clearly.

I thought so too.

@ghettosled - is there any coolant in that overflow tank? The '00 here was making an awful racket when the water pump started to go out, that mimicked bearing / lifter noise.

 

thank you all for the replies - I'll check these things out !after today.

 

Oh man, so interesting revelations. Coolant reservoir is full, changed and oil, installed new spark plugs, installed an extra set of spark plug cables, and reset the check engine light. All checking noises along the way. Exhaust needs to be repaired, but that’s for another day. Engine tick still there.

More major problem, the rust. In the process of checking these things, I notice some wetness along the brake lines to the rear. I replace these about 15 years ago, but are rusty again. Jacking up the car, the driver’s side rocker panel collapsed and fell off the Quickjack. Luckily, nothing major happened, but the car is in rough shape. Have to now lift the car from the front or rear sub frames. Though in the process of short cutting the brake line repair by just replacing the bad section, more leaks are popping up. Not sure if I should run all new lines or give up the ghost. Hate working on rusty cars.

 

Time for the old girl to retire that car is not safe. Given that level of rust the rear subframe is at risk of failure which will cause an uncontrolled spin.