Runs cold loses power and quits as it warms up

CALI CAL

MEMBER
1996 NISSAN PATHFINDER
3.4L
V6
4WD
AUTOMATIC
300,000 MILES

Runs fine when cold and as it starts to warm up it starts running badly and then it shuts off, let it sit for a few minutes and you can take off again but then it quits again. I changed coil packs, plugs, wires, MAF, ICA, and a couple other sensors and it had no change.

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

Can you monitor the o2 sensor data and see what the engine is doing when this starts?

I would expect that they would reflect the misfire or poor running condition as the engine warms up.

However, it could be a sensor issue as well so when the engine is running well, we need to see what the sensors are saying. If they are not reflecting the proper running condition when the engine is running well then, the sensor is most likely the issue.

Basically, the PCM is ignoring the o2 sensor data until the engine is warmed up. So, if the o2 sensor data is not correct then it is going to cause the engine to run poorly as soon as it starts to use it to adjust the air/fuel.

https://www.2carpros.com/articles/how-to-test-an-oxygen-sensor-02-sensor

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

Please see the chart below that will help with reading the o2 sensor data/short term fuel trims.

Let me know what you find with this, and we can go from there.

Image (Click to make bigger)