OK. Here's my story.....About a mile after filling up a nearly empty gas tank, my 98 Pathfinder quiet died at a red light. It started easily, but surged and slowed and quickly died, the CEL staying on. Visions of pumping out 20 gals of bad gas went through my mind. Luckily, we were only a half mile from home, a relatively straight shot with only two lights and we decided to risk it. We pulled into the driveway many stalls, starts, and a few horns and fingers later, and I proceeded straight to the toolbox.
The scanner reported 3 codes, P0100 - Mass Airflow sensor or circuit fault; P0325 - Knock sensor or circuit fault; and a P0100 Pending (I have no idea what Pending means). I start it up and it runs for a couple of seconds and dies. I pop the hood and start it up and it runs with the rpm constantly changing. There is also a tick tick ticking sound in time with the engine, similar in sound to a small electric discharge, coming from the area of the EGR valve. I shut everything off and clear the codes. I turn the vehicle on a it sounds great, strong, no ticking, nothing. I let it run for awhile and then hop in for a run up the street. I got to my turn around point and it dies. I limp it back home again. The P0100 error is back and so is the ticking.
While checking out the MAF, I notice I can sometimes kill the engine just touching the MAF or by just grabbing the wires behind the plug and wiggling very lightly. Now I wondering...bad gas? Bad MAF? Bad connectore? Bad wiring harness? I clear the code, and it doesn't always come back just by me killing the engine while playing with the MAF or the connector. Next, I disconnect the harness and check the power and ground circuits to the sensor and got a nice even 12v. I reconnect the harness and back probe the signal wire. I get about 1.3v at idle and it runs up to about 1.8v at 2k rpm. Finally, I crawl under the dash and disconnect the wiring harness from the ECM. I checked continuity of the white and black signal wires between the MAF connector and the ECM harness while aggressively twisting and bending the MAF end of the harness and connector. The constant annoying whine of my DMM confirms the wiring harness and connector to be in good shape.
I plug everything back in, clear the codes, and start her up. She sounds nice until I touch the MAF wires which kills it instantly. The tick (and the P0100) is back when I start it up.
So here are my questions: 1) Do MAF's die suddenly? Is a dying MAF so sensitive that just touching it or the wiring harness cause everything to fail? Can I rule out the gas? Should I have the MAF itself further tested? Should I try cleaning it? Should I just break down and change the MAF and hope that was it? Did the MAF problem cause the P0325 (which never came back)? Help!