Surging and low power when cold

Surging is normally an air intake issue or vacuum leak, but this is not limited to this. So, let's start with this guide which covers surging, and we can start working our way through this:

https://www.2carpros.com/articles/engine-surges

What I would also suggest we do is monitor the fuel pressure when this is happening. Here is a guide that will help with this as well:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

I assume that running through these two things, we will either find the issue or get on the right path. So please let me know what questions you have with this and we can figure out next steps.

Thanks

Thank you. The car is in PA. I am in S.C. now. I will check your suggestions when I get back to PA.

Not a problem. Thanks for letting us know. This link will remain active for however long it takes to get back to us.

Thanks for the update.

My car is a 1989 Mercedes 190d. I do not think it has an output for a code reader. I'm not sure if it has a mass air flow sensor or a manifold pressure sensor.

Correct. Your vehicle is what is known as OBD I and does not have the port under the dash. That started about 1995.

Also, you have an air flow sensor with the intake temperature sensor so this is traditionally called a mass air flow sensor.

Take a look at the info attached for more detail.

Thanks

Thank you for getting back. What should I have my mechanic check when I get back to PA.?

I would focus on two things to see if that points us in a clear direction. First, fuel pressure and then check for vacuum leaks using this technique.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Based on this we should be able to find something.

Thank you.