need help on high rpm Cavalier

Please help on diagnosis: 1990 Chevrolet Cavalier 2.2L 4Door AC,PS,PB 60K miles. Problem: I hear too high rpm based on the sound, car runs
okay but no power climbing hill or accelerate on freeway from 55 to 75mph, runs okay at constant 60mph. When going up hill, makes a tick-tick-tick noise on engine as if too low octane, or timing is retarded. Checked compression: all good at 150,150,150,150. I have a tachometer with 2 leads clips I do not know how to connect it since the Cavalier does not have a high tension coil with 2 posts. Cannot check timing since timing mark is hidden behind the serpentine belt and timing is by metal timing chain controlled by many sensors to computer. Coolant remain at green color no oil trace, oil normal yellow and not millky. But oil consumption is high at 1 quart every 1000 miles in 3 months, tail pipe exhaust normal no white or blue or black smoke. Spark plugs has white deposit and O2 sensor has white deposit (spark plugs and O2 snesor are all changed, still same). Changed gas to high octane, still same, used STP engine treatment, still same. Car has regular maintenance : water cahnged, oil changed, air and gas filter changed regularly. Question: how do I check rpm with my tachometer? What do I do to pinpoint what part to change?
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