I'm new to the miata world. I took a 92 in trade for repairs on a camry. My problems started the day it was dropped off. It drove great when it was dropped off. It sat for roughly 3 hours and when I started it back up it acted like it had a 2200rpm rev limiter. It would bounce off 2200 and fall to about 1500. After running for about 10 min it was fine again. I parked it in the garage and there it sat until my new top came, 3 weeks later. When I pulled it out of the garage it was back to the 2200 rpm rev limit, but I figured it was related to it being cold and again let the car run for 10-15 min. to warm up. This time it didn't matter it was still stuck at 2200........ Did some research found out about how these cars eat plugs and wires, and have issues with fuel filters. I had planned to do all of that anyway so I replaced it all. Checked the tps for proper position, checked the maf, inspected the intake tubes, and nothing 2200rpm still. Found a you tube video of a miata doing the same thing as mine the guy replaces the maf and its golden. So I replace the maf. and the car drives great for about an hour. Back to 2200..... Replaced the new maf with another new maf. 2200 rpm...... I go to move the car around and it suddenly starts working. I drive it all weekend. It works great. Monday the car is back to 2200 rpm. I checked all the grounds I could find, replaced the strap on the drv side (rear of head), ran a piece of 10 ga wire to all the grounding points (next to fpr, slightly below and back of fpr, plastic box under the booster) and under the new strap. Still stuck at 2200rpm. Oh and at some point i replaced the tps too. I gave all the pins on the tps and maf a slight twist to ensure good connection in the clips.

short of it:
2200 rpm rev limit/bounce - running rich - idle is low
Check engine light is off - no codes are stored

replaced:
TPS
MAF
plugs NGK
Wires
fuel filter
ground strap

Not sure where to go from here. And before anyone bashes me to search search search -- I have. Everything similar to my issue has been resolved by something I have already done.

 

Try the coils. They are notoriously failure prone and demonstrate symptoms like the ones you describe. I think I have one for a 1.6, but I don't know if it is any good (it came on a non-running parts car). You could probably find one locally for the same price as me shipping you this one unless you have time to wait.

Good luck.