Regarding oil change: Use either 15W40 mineral oil or Mobil 1 15W50 with a new oil filter cartridge. Suspect the oil level is low now. That's why the oil warning light comes on while you're driving. It's likely you need to replace the oil pressure sending unit since the pressure reads 0 at idle.

Remove and check the condition of the distributor cap, distributor rotor, spark plugs and ignition wires. Replace, as required. A neglected ignition system can cause the EZL unit to fail, and a new one costs around $2,500.

That car needs much TLC. Hopefully you are a DIY'er with access to discounted parts, or you will be spending thousands of dollars making that car right. Good luck.

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Fred Hoelzle