and decided to try to figure out why.
After much research and a thread on Miata.net, I had a number of things to check.
After replacing the plugs and wires, I had to dig deeper. After posting a video of my car running through first gear up a hill, most of the miata people felt that I was a victim of the “Short-nose” Crankshaft that was on all 90s and half of the 91s running around. The short version of what happens in these failures is the keyway on the crank wears away, allowing the crankshaft pulley to move around about 10 degrees.
The last time I drove it, it was running so poorly, I was forced to rev it to hold a decent speed on the inclines of the 400. This caused it to get a little hot, popping the radiator, about 2 minutes after I parked it. Grrr.
So I limped it into my driveway a few days later, and started tearing it apart. What I found was interesting. The crank pulley lined up with the zero mark when cyl 1 was at TDC. This mean my crank was fine 
Upon further investigation, I found this:
This is with the crank at TDC. Note the right cam mark “I” is a bit below the point on the back plate. My exhaust cam jumped a tooth! So after repeated attempts to get the timing right, I finally got it. A tutorial on Miata.net warned that it is a PITA to get right, but I eventually got it. I Put the intake parts back in place and started it for about 15 seconds. It ran quite a bit better, but not perfect yet.
Here’s a pic of the car if you are wondering what it looks like:
Now my concerns:
The first time I drained the coolant, it looked like this:
I flushed it a few times, but I don’t know if I got all of the nasty brown stuff out of it, or if oil in getting in the coolant. I am hoping it is just still a little dirty.
That is all for now. I must wait until I get a new radiator before I can really take it out and see if it is indeed better. However, there was a dramatic change in throttle response as soon as I started the car with the correct cam settings.