[quote=Filmfest Guy;6816118]Code 13 refers to an open circuit, not necessarily a bad sensor.
Rechecked the circuit (visually) for the O2 sensor. Appears fine.
Checked the error codes again (by grounding the test terminals) and I now have no error codes (just Code 12, which is fine)
Code 14 could be a overheating problem, What condition is your radiator in? If it is old and clogged, you will have overheating problems.
The rad is fine. Cleaned, has no leaks or cold spots. Thermostat, etc all new. Fan clutch appears fine...Overheating has not been a problem since the gasket leak.
Back to the reason for this post, could the 40mph "chuggle" be a coil or EST problem?