"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

[boxster914]

You guys are awesome!

My weekend of detective work is shaping up thanks to your help.

The red light I was referring to was the generator light.

Can you help me with the abbreviations from @lockwodo : PCV valve, AAR and CHT sensor?

If it ends up being the distributor is the 123 ignition replacement a good option to avoid future issues?

https://123ignitionusa.com/porsche-with-d-j...ncludes-spacer/

[Lockwodo]

You guys are awesome!

My weekend of detective work is shaping up thanks to your help.

The red light I was referring to was the generator light.

Can you help me with the abbreviations from @lockwodo : PCV valve, AAR and CHT sensor?

If it ends up being the distributor is the 123 ignition replacement a good option to avoid future issues?

https://123ignitionusa.com/porsche-with-d-j...ncludes-spacer/

PCV valve is positive crankcase ventilation. If you have one, there's a hose that connects to it right next to the oil filler. If the valve sticks closed or sticks open, it'll affect how the engine runs. AAR is the auxiliary air regulator. It allows air to be pulled into the intake for the first few minutes of startup but should close completely (internal heater element). CHT is the cylinder head temperature sensor. It sends a signal to the electronic control unit and affects gas/air mixture.

I've been thinking about the 123 disty also. I've heard it's great and also that it's difficult to dial in, and finally that the mechanical disty is better suited to the car and we best get the ones we have rebuilt. Seems to me that cleaning the mechanical distributor and making sure advance mechanism moves smoothly and points and dwell are correctly set (if you don't have a Pertronix electronic ignition or similar) and trigger points are OK is the first step.

[boxster914]

You guys are awesome!

My weekend of detective work is shaping up thanks to your help.

The red light I was referring to was the generator light.

Can you help me with the abbreviations from @lockwodo : PCV valve, AAR and CHT sensor?

If it ends up being the distributor is the 123 ignition replacement a good option to avoid future issues?

https://123ignitionusa.com/porsche-with-d-j...ncludes-spacer/

PCV valve is positive crankcase ventilation. If you have one, there's a hose that connects to it right next to the oil filler. If the valve sticks closed or sticks open, it'll affect how the engine runs. AAR is the auxiliary air regulator. It allows air to be pulled into the intake for the first few minutes of startup but should close completely (internal heater element). CHT is the cylinder head temperature sensor. It sends a signal to the electronic control unit and affects gas/air mixture.

I've been thinking about the 123 disty also. I've heard it's great and also that it's difficult to dial in, and finally that the mechanical disty is better suited to the car and we best get the ones we have rebuilt. Seems to me that cleaning the mechanical distributor and making sure advance mechanism moves smoothly and points and dwell are correctly set (if you don't have a Pertronix electronic ignition or similar) and trigger points are OK is the first step.

Thank you @lockwodo for the definitions!