"Trailer-hitching" bucking problem, Rapid detrioration from running perfectly Options

[boxster914]

Hi everyone

My perfectly running 71 914 1.7 D-jet has deteriorated rapidly this past week.

Early in the week I noticed what felt like a power drop out during a drive. It was very slight and only happened once and I wasn't sure I didn't cause it by unconciously lifting off the gas.

The next drive it happened a few times and was more pronounced. It was then that I knew this wasn't an imagined problem.

On the third drive it was like a bucking bronco, surging and stopping and the engine cut out a few times. It was undriveable.

Today it will start but won't run. The engine cuts out when I try to rev it and the red light comes on.

I've done some searching here but haven't been able to draw any conclusions or come up with an actionable strategy to diagnose the problem. I'm seeing people trace it to spark plug wires, air fuel ratios and bad distributors.

Is there a step-by-step process that you can recommend for me to get to the cause of this? (I'm a newb so I probably will need help with abbreviations like AFR, TPS, etc.)

Here is a video of it's rough idle yesterday when it was still running.

https://youtu.be/n61CP6O8UgM

[BillJ]

This exact behavior happened twice in my 75. Went through two filters before simply changing out the tank. Never had another issue.
Changing just the filter may solve though.

[Lockwodo]

This exact behavior happened twice in my 75. Went through two filters before simply changing out the tank. Never had another issue.
Changing just the filter may solve though.

So I monitored the fuel pressure when the engine is running and the missing issue is happening. It's rock steady at 29 PSI. So doesn't that rule out the problem being related to a clogged fuel filter (which I replaced anyway) or crud in the fuel line/tank?