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I’m thinking that it may have been a stuck EGR valve. Nothing has changed whatsoever except the outside temp being 30 degrees cooler and wet roads. My instant economy meter is reading 6.1 mpg, which is what it used to read a couple months back. I haven’t hand calculated yet because I haven’t filled up yet. But at a half tank on the fuel gauge, I’d be between 280-310 miles. I’m currently at 250 miles and right between 3/4 and 5/8 tank. I don’t think a leaky injector would’ve corrected itself or leak in boost system either. Valves wouldn’t have given themselves an adjustment either. Just more reason to de-mandate ASAP.

^^---- Wouldn't the crossover pipe constantly be hot if that were the case? Seems if exhaust gas was coming through all the time, it would be near the same temp as the manifold. Are you having any boost psi issues now?

Stuck egr would have thrown a code.

(11-04-2021 )tree98 Wrote: [ -> ]Stuck egr would have thrown a code.

Not necessarly, the motor on the valve could be still going back and forth, but the butterfly valve could be hung up open.

The differential pressure sensor would catch that and throw a code. These engines are very particular about how much EGR they are getting, the ecm keeps a close eye on it.