" I agree, I don't like the engine stuttering like that, but up until the original DME failed, HPFP fuelpressure never dropped under ~1500 psi, and there was no stuttering, so I think the HPFP is on it's way out. Regardless, it was interesting to me how different tunes come up with different codes for what is basically the same issue. Hopefully I should have the VTT modified HPFP in a few days, so I can start testing again, and then I'll send you some logs. Don't really want to stress the car as it is running atm. "

" OP, that's really not very good news. I'm still waiting for my VTT HPFP upgrade to clear customs (it's taken them 12 days so far....), and my plan was to run E85 with my RBs. I'm around 21 psi midrange, and sometimes my HPFP falls flat to ~900 psi around 4000-4200 rpm, but @ 5000+ it's back in business.

I think it may have a lot to do with the tune as well. On the BMS flash map (both the race and E85 ones) + map 5 I recently got a 29DC code and a limp even @ ~18 psi, but with the PTF map from Dzenno I still don't get a limp, only occasional "stuttering" during midrange acceleration due to the drop in HPFP pressure. Actually before my DME failed I never had these problem with my current HPFP, so it may actually just be going out. It's "only" my second one in 85k miles...

Well, I'll know more when the upgraded HPFP finally clears customs and I get it installed. I use the Walbro 455 pump, so it's similar to your setup. "