[hardflex]

from a web search i found this--

1. HYDROCARBONS (HC - PPM)

Hydrocarbons are unburned fuel. A properly running engine will produce some HC's. On most late model vehicles in good mechanical condition and equipped with functional emission controls, HC measured at the tailpipe will be very low.

The presence of HC in the exhaust shows unused energy (fuel) going out the tailpipe.

Excessive HC in vehicles is the result of incomplete combustion, which could be caused by ignition malfunction, mechanical faults, vacuum leaks or fuel control or fuel management problems.

Example of:
An electrical defect may be caused by a fouled spark plug, shorted or broken ignition wire or a carbon tracked distributor cap.

A mechanical defect may be caused by a defective valve train component, weak or worn piston rings or excessive timing chain or belt wear,


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sounds like a tune up would fix it. have you looked for evidence of rich burning? tail pipe dry black?

Lemme see if I can get Ron Meier to come to this thread with local shop recommendations. He lives in Crestline, I think, not too far from you.