Does it still hold pressure at the schrader if you pinch the return line?

George

 

I think autozone just gave me a crappy one. Cheep one from ebay I ordered a while a go for cheap testing came in today. I installed it and it was the same so I adjusted it via the allen screw in the back of it to 58 psi. It holds but still get p0300.

Here are new fuel trims.

 

Also running pressure is like 55-58

 

Is this true

 

Turns out i was able to use vcm scanner with my RTD from my mustang. Misfire counter showed Cylinder 1 and 3. Tuned out the had no compression. I pulled the head and saw the gasket was blown between them and also a hairline crack on head in that area between a water jacket and valve in Cylinder 3