Hi Steve,

Personally, I would start with an inline pressure gauge b/w alda and turbo. Highway loading is very different than in town loading (higher boosts etc) which affect the supply to the alda. If something is leaking on that line, now that its colder, you could see a quick drop in fuel supply - my current thoughts just to start.

Has the wastegate been modified?

Hows the plumbing and linkage (on wastegate) etc..?

I will be thinking about this the next few days and add more thoughts.

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