Well, I come back from school for Christmas and my car is slow again

My parents have been driving it occasionally while I was gone so it just doesn't sit and rust. Recently they drove it and it all of a sudden was really low on power, like the boost line to the ALDA was clogged. Really flat power band like a non turbo car. I removed the ALDA lines and fittings and blew them out and cleaned them, but same result. The switchover valve passes air fine. I even tried directly connecting the ALDA to the manifold with just vacuum fittings and a coupler. No dice.

Tried resetting the EDS by leaving the negative battery cable off overnight. Still slow. Don't have a boost gauge so there really is no way of testing the turbo, but I did pull the pipe to the turbo and check the compressor. It felt within spec and turned freely. I'm starting to suspect the fuel system. I didn't see any bubbles larger than normal in the pre-filter, and I haven't taken the spin on filter off yet as I don't have a replacement at the moment. It starts right up and doesn't hesitate like an engine with a leaky fuel system would do. Should I just change the filter and go from there? I did put a couple gallons of B99 in there about 1500 miles back, could gunk released by that be plugging my filters?

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Dale

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1990 300D 2.5 Turbo -155k
2000 E430 - 103k
2014 Jeep Grand Cherokee Ecodiesel 4x4 - 11k
2014 VW Passat TDI SE - 7k Bro's Diesel
2006 E320 CDI - 128k Pop's Benz

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