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High HC means incomplete combustion. Given that you've replaced the O2 sensor (Lambda Sond) so the ECU knows how it's doing, consider inefficient combustion on the ignition side from things beyond the control of the ECU. Timing is not adjustable on these engines, so generally nothing to worry about there. Think more along the lines of plugs, cap/rotor, wires, even a weak coil. Apart from the coil, these are routine replacement items and you don't need to test them to prove they're a problem, better to replace them on a timely basis before they become an issue
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now
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