I'd have to go out and look on my '86. On the m20 update motor, it's mounted right on the front of the engine close to the crank. It's a 2 wire magnetic sensor and picks up it's signal from the toothed ring on the front of the engine. Why is it worse on an incline? maybe it's just a bad connection and the wiring harness shifts just enough to exaggerate the problem, or the sensor is loose in it's mount, and it's shifting. It could also be minor corrosion on the terminals causing just enough resistance to deaden the signal unplug it plug it back in, could also solve it. Not saying it's definitely the sensor does the engine light go out while cranking when it doesn't start? (I'm just keying off of the rpm gauge)