So my 2004 Mazda 3 (JDM 1.5L model) stalls and hesitates during acceleration after a cold start. However, It runs perfectly after 7-10 minutes of idling. The only error code I have is for an upstream o2 sensor heater control circuit. I've had it since the day I got the car 6 years ago, but the problems started showing up just recently.
I have replaced the MAF,MAP sensors. Checked for vacuum leaks. Cleaned the injectors, cleaned the throttle body. The problem seemed to go away for a day or two then came back. The long term and short term fuel trim levels are close to 0.
Here's an event worth mentioning. A few days ago, I started the car and didn't let it warmup. It was raining outside. It stalled on me within minutes and wouldn't start back up. After trying for a couple of seconds, it started and died after 10-20 seconds. I pulled over and let it warm up. After which it ran fine. Then on my way back home I drove over a small puddle. The car stalled immediately afterwards and wouldn't start. After trying for a few seconds it finally started. I checked the air intake and other stuff for signs of possible water ingestion by the engine but thankfully there were none. The next day I saw a CEL for the Crankshaft Position Sensor.
I checked the wiring, cleared the code and it hasn't come back yet. But the car still stalls if I don't let it warmup for at least 10 minutes before driving it. Do I need to replace the Crankshaft Position Sensor? Is it a common sign to have the engine stall/hesitate due to a bad Crankshaft Position Sensor only when it's cold?
Your feedback would be very much appreciated.