Hi guys! OK, I installed the new O2 sensor. Replaced the popped heater hose, along with a new thermostat as a 'just in case' measure.

Got myself a new DMM that reads duty cycle. Engine cold, pins 2 & 3 on the X11. 70% duty cycle KOEO. Start car, immediately drops to 50% and stays there for a few minutes until it goes into closed loop, where it quickly rises to ~90%, and no matter what I do with the mixture screw on top, it stays there. Give it some throttle, and DC drops into the 50's, and then pops right back up to 90%. Footnote - cold start still sucks, has to crank and crank, seems like it's slowly, one at a time, firing off cylinders until it'll stay running on it's own without holding the key.


What gives guys? What do I need to look at?