Repair-It

I have had at least a half-dozen long-cranking evolutions on the WK2, most evident when sitting 6+ hours. It became much more frequent in the last two weeks or so, where more than about 75% of cold starts it would act up. I pulled the fuel manifolds and fuel injectors out of the intake on both sides and inspected for any evidence of a leaky injector. Nothing found, so I resigned myself that it was likely the fuel pump anti-drain-back check valve that was likely causing fuel pressure drop, and considered ordering a fuel pump (Delphi pump is about $200 on RockAuto - requires removal of the cat-back exhaust, driveshaft, and fuel tank to replace). As a last-ditch effort, I bought a bottle of Techron fuel system cleaner, and "B12" cleaner also at Walmart since it was cheap, and ran them both in about 15 gallons of gas left in the tank. Some city driving, some overnight sits, and then a long highway run. So far I'm 100% fixed since putting it in last week - we'll see how long the trend stays. Certainly worth trying another Techron dose since it appears to at least be helping.

Those are both pretty good products. But not sure it would fix a fuel pump check valve.

Cold started this morning fine, but had a long crank after only like 3.5 hours of sitting. Weird

I feel like you've reached the point where it's time to drive around with a fuel pressure gauge taped to your windshield.

I ordered a fuel pressure gauge off Amazon that includes the T/quick connect adapters. Should be in this weekend, but I won't be able to start instrumented runs until the end of next week at the soonest. Started fine today even after >24 hours... I'm inclined to try more B12/techron before I dive any deeper since it's back to more intermittent...