Brown beauty on duty? Nah, that's just me getting ready to take a look under the hood.
Your information is helpful, but you've got a ways to go before we can really help you.
So far, we're only stabbing at something in the dark.
You did clear up one thing.
It was a LOT more than a check of the timing which led to the different timing light results.
Working on cars is simple, and by varying ONE variable, you can easily see if it improves or hurts the whole picture.
You actually removed the distributor, but even so, we don't get a clear picture.
Let me explain.
I can tell you that I removed the distributor, and put a new O-ring on.
It is left up to you to decide
-if the vacuum lines were disconnected at any time
because you don't have to disconnect electrical lines, distributor cap, rotor or vacuum lines to change an O-ring, right?
Let's just follow the train of thought about the vacuum lines.
Suppose you DID pull not only ONE but BOTH vacuum lines.
(Again, we are taking a guess/stab in the dark as to what you did...)
We would investigate the possibility that the vacuum lines to the distributor were reversed.
This is an easy check and doesn't require any tools.
You'd simply reverse the lines and see what values you get with the timing light.
Then, you'd report back in this thread and let us know what happened so we could either check that off our list or go to the next 'step' in our check of your problem.
My point is this.
You've got some real helpful people willing to back you up, but you are going to have to make a little better effort to solve this 'problem'.
When I asked you about the 2 vacuum pots on the distributor, you sounded like you were wading into unfamiliar territory.
If so, fine.
That's what this forum is for.
You post a problem, and together we help you solve it.
Then, you post the results, and when someone has a similar problem, you take a little of the weight off our shoulders and help them.
Now, back to my question about the distributor vacuum pots.
You wrote, "How do I do this and what should I be looking for?"
The usual way we test a vacuum advance on a distributor is to remove the hose and hook up a vacuum tester. We apply the normal vacuum the diaphragm would see from the engine, and see if the needle holds steady.
This tells us the diaphragm is not cracked and holds vacuum.
In your case, you have TWO hoses going to the distributor.
There is nothing odd about this.
You'll simply do this twice, once for each line.
If you have never done this, you will need to obtain a vacuum gauge.
Then, report your findings.
You can either type in your results, or post a video of the actual test.
Your distributor sees ported vacuum, so it isn't necessary to crank down on the vacuum gauge.
Those diaphragms don't see a lot of vacuum until you open the throttle while heading down the road.
Your distributor vacuum diaphragms will eventually crack with age, and this may be your underlying problem.
It can manifest itself as a drop in fuel efficiency/gas mileage, or the diaphragm can allow atmospheric air to enter the system unmetered, and cause a 'lean burn' condition, contributing to a 'burnt valve' situation.
You'll get GREAT gas mileage, and she'll burn lean, mean, and hot.
While we're at it, you should post a picture of your distributor...how about a close up, something like this:
No, I'm not trying to sell you that distributor; it is just one I've cleaned and put away. Usually, I check the vacuum and give it a 'value' so when I need it, I'll know if it can be used as is or not.
So post a few good shots under the hood. The more effort you put into this thread, the more you'll get out of it!
If, indeed you have a problem with the vacuum advance/retard pots, then you'll have to remove the distributor and get replacements. This can be done either by a reputable rebuild shop or a junkyard replacement, as the Sprint Metro distributor can accept other vacuum units from other junkyard vehicles.
While you have the distributor off, Fainya could rework it, replacing not only the inner bearing, but also the seal. It is not that expensive, and when you compare the mileage now and after he reworks it, you will recoup any money you might spend in short order. No, I do not get a 'cut' of his fee, and he barely makes enough to cover the cost of the parts he installs. I have recommended him because a.) he is a member here and b.) he has a reputation for doing quality work on distributors.
Those replying in your threads are somewhat familiar with the Chevrolet Sprint and drunk or sober, rain or shine, day or night they can usually figure out the problem. The Chevrolet Sprint is fairly simple, but it does have a few complex systems, and the vacuum routing is one of the more complex systems, especially on an A/C vehicle like yours. The cars do not care about our personalities, but if you are relying on a tired and leaking distributor, it is something you shouldn't ignore. Take the time to repair this problem correctly so that you will improve the reliability of your daily driver. Having crisp, clean spark is very important in a 3 cylinder, and your distributor, after all these years is probably telling you something.
Regarding your 35-37 gap, the Haynes shows the gap should be 39-43 way back in Chapter 1.
If one of your vacuum diaphragms has bitten the dust, you might want to invest in a new ignitor while Fainya has it apart. I've noticed that a new ignitor will smooth out the idle much better than changing the gap. As far as having a hard time starting the car, you may have a problem with the MCS, but that's better addressed in another thread at another time. There are several nice videos showing you how your MK1 SHOULD start on this site, and this site really is chock full of supportive information for your vehicle, unlike many other vehicle sites.
As you've heard many, many times...a car only needs spark and gas to run. Getting spark right is easy on a Chevrolet Sprint Metro. You'd be amazed at the people I've met through Teamswift who take the time to put quality parts into their Chevrolet Sprints. None of them regret it.
Good luck and take a closer look at that distributor!