Just got our 2000 Limited T&C...it has right at 100,000 miles, and for the most part it is very sound mechanically. It is doing this strange thing occasionally when stopping. If we brake gradually, and only apply small amount of pressure to brake pedal, it works great. The problem seems to happen if we abruptly push too hard on the brake pedal. There is a jerk in what feels like the transmission, and then the engine runs VERY rough (like it's going to stall) until we give it gas and then it runs fine until the next time. Does anyone have any ideas on what could be causing this? Thank you in advance.

 

Does anyone have an idea?

 

It sounds like you may have a ruptured diaphragm in the master cylinder power booster. It is dumping air into the engine causing it to go lean. It may not be braking very well, either.

 

Thank you for the response. That actually makes sense, and could also explain why the cruise control doesn't work. How can I troubleshoot this before I replace the wrong part?

 

If I am right about this, you should have the same problem if you apply the brakes hard while standing still. In that case, while the car isn't moving, clamp the vacuum line off with a vise grip and see if the engine still wants to stall upon brake application.

There is a one way valve in the vacuum line. The valve could be defective but you may not be able to obtain this without buying the entire booster and /or master cylinder. At 100,00 miles I suggest buying the whole unit.

 

Thanks again. I will do some further troubleshooting and report back here.

 

Out of curiosity....could a bad torque converter clutch also cause these symptoms?

 

The torque converter clutch may cause the car to jerk and stall only as the car comes to a full stop. It would only be related to braking in that the brakes cause the car to stop. The real test is to see if the engine tries to stall when the brakes are applied while the car is not moving.