Questions and Answers

Nissan Pathfinder Cold Start Stalls Q. Hi Vince, I have a 1989 Nissan Pathfinder 3.0 V-6 with 168,000 miles on the engine. When I start the truck it starts up and then immediately dies. After starting it a second time, it will continue to idle around 750 rpm. However, when I start to drive it, it will lose engine power and almost stall, and then return to normal idle. I'm not sure what the problem is.

Prior to this problem I had the following items replaced by a mechanic: the fuel pump/sending unit, new timing belt, distributor cap and rotor, wire set and spark plugs. I'm wondering if the O2 sensor is shot? Any ideas?

Thanks...

A. When the engine is cold, the O2 sensor is out of the loop, hence the term "Open Loop" operation. When the O2 sensor warms up enough to kick in, the engine goes into "Closed Loop" operation.

I would first check the computer for codes and see what's there. I think you have a bad Coolant Temperature Sensor. If it's reading high, it will cause a hard cold start and poor warm engine operation.

Diagnostic Trouble Codes