Stalling under load - '93 Legacy 2.2, old fuel filter

[BB's93LegacyL]

Entering the highway, as I tried to get up to speed on a gradual incline, the engine became unresponsive to throttle. After coasting awhile, the engine surged once more, then stalled. As soon as the car coasted to a stop, I turned the key and it started right up. I drove across town on city streets with no sign of the problem. I thought it must be a fuel delivery or electrical problem. I did some checking and came to the conclusion that the fuel filter was likely the original from the factory 23 years and 166K miles ago. If so, it had about 7,500 gallons of gas run through it. Since it was way past due for replacement, I decided to replace the fuel filter, hoping that was the problem.  The installation took only 10 minutes because of the convenient location in the engine bay. The lines came off easily, probably because the OEM filter was stainless steel. I have not had further problems, so I am keeping my fingers crossed that this was the solution. I recall now that the car had a slight surging in RPM at warm idle. That problem has disappeared too.

 

After the new filter was installed, I was curious about what the inside of the filter looked like. A friend took it in his shop and broke it open. This was not easy because of the heavy gauge steel. The filter medium looked pretty bad. I held a piece of it up to a flashlight to see how much light passed through -- barely any. I have attached photos that show how bad this looked.

 

I hope this was the cause of the stalling problem, and not some other intermittent bug. It's been running fine since the repair 2 months ago.

Edited November 3, 2016 by BB's93LegacyL