Surging when applying the brakes

HI and thanks for using 2CarPros.com.

Based on your description, I am not 100% sure I understand. Do you mean the engine surges or the car feels like it does?

If the car feels that way, chances are it is a brake problem. Basically, rotors or drums can warp over time giving the feeling of a surge In most cases, you will feel the steering wheel shake if it is the front. The rear is a different story. What I do is when moving, apply the hand brake keeping my hand on the parking brake release the entire time to determine if it is a rear brake issue. Caution: If you try this technique, you must have the park brake release pressed the entire time and gently ease into the park brake. Do not jam on the park brake because it can cause you to lose control of the vehicle.

If you determine that the brakes are not the issue, I would next recommend checking for an engine vacuum leak, especially if the engine RPM surge when applying the brakes. The power brake booster is powered by engine vacuum. Since this only happens when applying the brakes, there could be a leak. Here is a link that describes how to check for an engine vacuum leak:

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

Check these two things and let me know what you find.

Take care,
Joe