Stuck and Need Help

[JimC42]

I have a 1987 Pathfinder and it has a problem that cannot seem to be tracked down:

Sometimes (not all the time) when the engine reaches about 3000rpms or about 50mph, one of the fuel injectors stops working which causes the engine to skip and sputter like it is running out of gas. If you let up on the accelerator, it smooths out. What has been done already:

• Fuel filter replaced
• Fuel Pump replaced
• Mass Air Flow Sensor replaced
• Checked voltage at the malfunctioning fuel injector and when it is acting up the voltage is 0v
• Applied external power directly to the malfunctioning fuel injector and it started working correctly
• Took the vehicle to an auto electrical specialist to look at the wiring. They kept it for a week and charged me $500, then they said that they could not find the problem and if I wanted them to keep looking it would cost $1000-$2000 more, with no guarantees.

The body (Interior and exterior) is in great condition and it only has 84K miles on it. It was my dad's and it sat in the garage of his mountain cabin for its whole life, being driven maybe 10-15 times a years when they went to the cabin. Other than this strange problem, there is nothing else wrong with it.

I am at my wits end. Any advice would be welcome

Thanks,

Jim

[4xq]

Just to be clear, are you saying that when you supply voltage to the injector, the engine runs smoothly at all rpms and the problem seems to be fully corrected at all rpms? What engine?