First off, I want to say that DRAG sucks for not sending any instructions or turbo gaskets with this kit. I really dont know of anything else they left out.

The problem that im having is that the engine CEL comes on whenever I start to build boost. The check valve is installed as such:

TB <- MAP As installed, the MAP can sense vacuum only and closes when boost hits the mani. There is only one line connecting the TB and MAP. After the CEL comes on, the engine idles lower, sometimes stalling, and eventually wont run at all. Once the MAP is reconnected in its standard form, it will start and run very well, as long as I dont build boost.

Only one check valve came with the kit. Is there two that are supposed to be installed?