I would recommend troubleshooting the EZL (ignition) first. The manual recommends this as well, and I have spent lots of time troubleshooting the CIS when the problem was in the EZL.

I would do a quick pass at the cap, rotor, rotor driver, wires. Run it with a strobe timing light. After this all checks out OK then I would check the Lambda.

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89 300te 222,222
92 300e 190,000