Nissan Repair: 1995 200SX, rpm 2000, fuel pressure

Question
Our '95 200SX has +/- 135,000 miles.  It has been running great.  Recently in high gear (auto) and low rpm (+/- 2000), I noticed what felt like some missing or intermittent power loss.  When you drop it down a gear and increase the rpm, you can't feel it.  Then yesterday morning, out of the blue, it did not start.  It would just turn over as if there was no gas or spark.  I pulled a plug wire and it was getting spark.  So I pulled a gas line and it pumped gas.  Still would not start.  I figured if it had spark and gas, then maybe it had no oxygen, so I opened the air filter.  With the air filter open, it started... barely, and smelled like hell.  When I closed the air filter, it started and ran like normal.  But I didn't fix anything!  Keiko took it to work today and it ran normal, except she noticed the same chugging in overdrive at +/- 2000 rpm.  My question is, does this sound like a dying fuel pump?  Or a bad regulator?

Answer
Allen,

I would check the fuel pressure to get a handle on what the pressure is.  The pump, relay or regulator could be your problem.  But, to be sure you need to get a gauge and check the pressure.  Also, it might be a stuck injector.  Take each plug out and see if any are really black.  That would indicate a stuck injector for that cylinder and that would flood the car and that is why it started up once the filter was removed.  So, check the plugs first.  Does not cost anything to remove the plugs and check them.