I have a 2007 Lexus ES350 with 370,000 kms. When I start it, it has a stumble/misfire that lasts until it reaches operating temperature. Once warm the stumble goes away. There are no codes. Is it the Coolant Temperature Sensor?
Probably a leak. Check FAQ and see if it helps
You could hook up a cheap scanner that will tell you what the ECT sensor is showing when the car is cold but if that isn't the problem you may want to smoke test it for an intake manifold gasket leak.
Typically with an intake manifold gasket leak you'd also notice higher than normal rpms until the car warms up
The cars rpm’s are normal on start up, just a stumble until warmed up. If I put it in gear, the stumble gets worse because of the lower rpm’s. There is no stumble while driving until I stop at a red light. Once the car reaches operating temperature, the stumble is gone completely.
Scotty read your question and answered it