Deffinitly try replacing the themostat. If the O2 sensor is unplugged before starting does the engine still have the idle problem. Mine has always gone through a minor idle instability phase during warm up. I've concluded that the Lambda system starts modulating the mixture before the sensor is up to operating temperture. This then results is too lean a mixture for a short time.

hi there. as i understand it the 02 sensor signal doesnt come into play until it heats up, and lambda is in default dwell until then. i installed new 02 sensor and reading fluctuates very very quickly yours might be lazy. check and adjust throttle switch per bentleys. cleaning throttle body and idle control valve helped me. my 85 turbo starts right up when weather is cool in morning but hard to start when hot and sunny. im thinking c.p.r. will test tomorrow with new guage from j.c.w. if i can figure out how. please post back if you make progress as this is where i learn. good luck

I have no proof to back this up - my car does the same thing.

But, with fluctuations in oxygen like that, I almost wonder if the gas fluctuates in the same manner. I'd almost want to suspect the Cold Start Injector assembly. Maybe the regular injectors are overcompensating for what the cold start injector isn't doing???

Once Again its speculation, but maybe a start.

Smith

I have no good answer but make sure the mixture and base idle are set as per the Bentley. Then check the frequency valve circuit on the fuel injection relay and the freq. valve relay. Not sure where to go then. I wonder if the thermal vacuum valve is involved? Porkface??