1992 S4 all of a sudden not making any boost. In dash digital gauge reads 1.0 bar all the time. Changed Blowoff vavle as it was leaking when tested, didn't fix it. Tested waste gate and that is working fine. Any ideas. Simple test I should perform???

Thanks

 

The problemwas the little boost line at the back of the engine that goes to the ecu. Thanks anyway.