'91 300D 2.5- turbo beginning to fail??
 

Turbo has decent boost when going from a dead stop, but has little to no power above 30mph. When using the kickdown while moving, there is no turbo boost. What do you guys think, is it time to rebuild???

thanks

I would be real surprised if it was the turbo. In my opinion turbos don't work sometimes and then not work other times. More than likely the egr valve/turbo boost control system.

I agree. If you're not familiar with the computer on this car, get the blink codes read by somebody who does. Most likely you have a loose connection, bad sensor, or bad vacuum transducer.

To make sure it is the computer and not the engine, turbo or IP, temporarily plumb straight vacuum to the wastegate actuator under the turbo and see if the power improves. Be careful when you're doing this because boost can climb to dangerous levels. If it does improve, you have to track down what's making the computer unhappy ;)

Codes are easy to read. You can do it with an analog meter. Count the needle swings. It was pretty easy. Check for Vac. It's not that hard to trouble shoot. There's lot of great info on this site.