Have two 04 visions that I am told have turbo issues. One is the turbo speed sensor keeps cutting the boost pressure. We have tried two new sensors and still have the same problem. One mechanic mentioned maybe the turbo shaft is "floating" and the sensor is loosing the signal. Is this possible?

The other one has air system troubles. The dryer is blowing off every 20 seconds, this doesn't happen constantly, but will be fine for half a day then start doing it again. We changed the compressor, dryer and govenor recently and have had troubles since. One mechanic is wondering if we are loosing air at the turbo some how and this is triggering the govenor. There is no visible air pressure drop on the gauges before it pumps again.

Any ideas or comments would be great. Don't want to spend $4500 on a turbo and still have the problems.