Rotten egg smell and chugging could be a cat converter being plugged up. A temp gun on the cat could show that, or at night it could start glowing red. Double check that no coolant is dumping into the oil and that you didn't bump a major vacuum line off the throttle body.


If you didn't bleed the coolant system of air after the thermostat replacement, you need to do that still. There is going to a giant pocket of air that won't allow coolant to flow properly.