Brand new GM Turbo Wastegate Actuator p/n 12456422. Fits all GM-4 Turbos. GM-4's were used in 94-95 C/K pick-ups, suburbans, Tahoes, and Yukons.

The actuator contains a diagpragm and is controlled by vacuum based on a command by the ECM. It DOES NOT contain a spring of any kind. Vacuum must match fuel rates for your diesel to work properly. This is why those spring gadgets sold by the scammers just do not work. They not only not work, but will trip codes too. The computer must be in control of boost. If you want to raise boost, you upgrade the chip or ECM. Fuel rates have to match boost. Do not eliminate the vacuum system or wastegate actuator.