Couple weeks ago my Pathfinder would occasionally lose RPM's at idle and sometimes die but started right back up. Then it began dying while driving regardless of speed - RPM would drop to nothing, car would die but would start back up. Yesterday it did this many times and then finally just refused to start anymore. Plenty of fuel. Put in a new distributor, spark plugs and plug wires. Fuel pump and filter only a year old.No clogs, etc. Checked spark, getting plenty. Checked fuel pressure, fine. Any more ideas? ... thanks
There are two test that I can think of. Injectors and timing.
Injectors are the easy test. The best way is to listen to the injector with a stethoscope while cranking. You will hear a knocking sound if the injector is firing. The second best is to use a noid light or equivalent. If the light is flashing then the injector is firing. This is not as good because the noid light is a very light load compared to the injector and may show a false positive if the injector driver is weak.
The timing check is a bit more challenging. Remove a spark plug and install a compression gauge tube. Don't connect the actual gauge to the tube quick connect. Then install a spark tester on the spark plug wire of the same cylinder. Place your thumb over the tube and watch the spark tester while cranking. The puff under your thumb and the spark should be at exactly the same time. If they are not then there is a timing problem. This may not be a timing belt issue, it may be a flex plate issue.
PS if the vehicle is sparking then most likely the crank sensor is ok.