1997 2.2 Cavalier Spark problem

Have a 97 Cavalier with p0300 (random misfire) and p0172 (rich fuel condition).I'm assuming the rich fuel condition is a result of the un burned fuel hitting the o2 sensor post catalytic converter? anyhow,
had it on a scan tool that reports cyl 1 and 4 are missing intermittently. Changed plugs/wires and the coil pack for 1&4. Still missing.on 1&4 Changed ignition control module. Still missing on 1&4.... What tells the ign control module to fire the coil pack? Crank position sensor?
When looking at graph on scantool (Modius Snap On) while attached to plug wires shows (on 2&3) like EKG blips (even height spikes with flats between equal spaced). On 1&4 Some full spikes some half height and some flats where even spacing would indicate spikes should be. (yeah, not the correct terminoligy, but I'm doing the best I can...)
I'm about $280 into parts that I didnt need... Anyone got an idea?
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Crank sensor or it's reluctor wheel would be the most likely culprits. BTW misfires will show lean on your O2, because there's loads of oxygen. A P0172 indicates it's adding fuel, which would be consistent.

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Sounds like dirty fuel injectors to me. It was a problem a couple years back, GM issued a TSB about it as well.
Chris
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I had to replace all 4 injectors this past year... Guess I'll swap 1&4 for 2&3 injectors and see if the miss follows the injectors. If missfire doesnot follow injectors, how would I check the crank sensor? Jason
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