I've read through a lot of stumble posts but none seem to match my exact issue. My car starts and runs well. It pulls strongly up to 2000 RPM at just about any throttle setting, but then it's like the motor hits a momentary brick wall where there is no power. Then a split second or so later it pushes past it and pulls strongly the remaining distance to redline.



Does not seem to matter whether motor is cold or warm, or what outside temperature is. Gear also seems unimportant. But it's pretty much precisely and only at 2000 RPM indicated.



Even though mine is not a turbo, I read the thread on turbos and resetting the ECU by pulling the battery or unplugging the ECU. That doesn't seem to affect mine (it has a battery disconnect from the previous owner that I've tried). Years ago I had a basically identical 1982 car that didn't have the issue. I haven't found a decent mechanic locally for older Japanese cars.



Any ideas or suggestions appreciated...

 

These are vey tricky problems. The short duration of the problem at 2000 rpm has me stumped. I have an '82 and had a problem with missing through a larger range of RPM and problem turned out to be a combination of timing controls. There are four timing controls (fuel injected engine): Static, Vacuum, Servo, and mechanical (centrifugal). The servo control is simply an electrical switch operated by a cam on the throttle linkage. This cam is set to make the switch somewhere about 1400 RPM. The servo goes abruptly from about 12 degrees of advance to 0 and the centrifugal advance takes over. If the cam is not set correctly, this could cause a short problem. I'm really guessing here.
The distributor is complicated also; after rebuilding the vacuum canister and dissecting the distributor, I found it to be very corroded (134,000 miles) and worn and had previous repairs. It was working but not well. I found the last distributor on the planet (e-bay) and that fixed the problem completely.
Good luck, keep us informed.