2002 Lexus ES300 178,000 miles. The thermostat needs to be changed; temperature gauge stays halfway cold with cold weather. With warmer weather, the car fully warms up and by then, there is hesitation when accelerating from a stop. The transmission also feels very sloppy and jerky, no matter what gear. When cold, it takes off the line faster and transmission feels more solid. I have replaced spark plugs and both the VVT solenoids. Engine has code for b1s1 o2 sensor and heater not working; not sure if that will change anything. I'm worried if I change the thermostat, it will always run poorly. What can I do to make it run good at all times?
Transmission appears to be a separate issue.
the B1S1 indicates the heater inside the sensor is bad and that most certainly can cause make a car run poor, I’d change that for sure. The rest of your issue could be anything from a dirty throttle body, etc. if you have a scanner with data take a look at that.
