The car is a 2004 Evo 8 tuned on Tephra v7 with speed density.

Mods:
Kelford 272 cams
FP Red
Supertech Valve train
ID1000 Injectors
255 in tank feeding inline 044
Full TBE
Factory ignition

I have had the car running on this setup since November, been over 520 whp since then and have had zero issues. The car is on E85 and has been since November. Numerous passes at the track as well, about a week ago I took it to the track it ran fine on the way, ran fine at the track, and drove home with no issues. The next morning I went to drive it and jumped into it getting onto the highway and it started to miss at around 6500 rpm. It would hit 6500 fall on its face almost as if the car turned off come back and then go again until I let off the throttle. We put the car on the dyno ran through the gears and made 10 other pulls before pulling it off. as soon as I got back onto the street in front of our shop the car started doing the same thing.

I have replaced:
Cam sensor
Coils and wires
Plugs (bpr8e gapped at .21)
044 fuel pump
255 fuel pump
fuel pressure regulator
Relays for both fuel pumps

Other things I have tried:
Turning the boost down and running on just wastegate pressure
Boost leak test (the car would hold 20psi for some time before starting to drop)
Draining tank and replacing fuel
Disabling the knock sensor

Things I am tempted to replace:
Owner

I will upload whatever I can as far as logs go whenever I get home, the last one we pulled was at around 68% IDC, 303 Load, 20 Lbs boost, and 7 degrees timing advance and out of nowhere all stats stay the same and load drops to -12

Thanks for any help,
Chance

 

Are your coolant lines pressurizing? Make sure your vacuum line is still attached to your Fuel Pressure Regulator. Check all vacuum lines. Other than that not sure. I would try to go dual in tank if possible, the 044 inline setup is not ideal and will kill your intank pump over time if you kick it on after a certain boost or cause your idle to suck ***** if running all the time. I use to run that setup, so I know the difference the dual in tank makes on driveability.

Does the breaking up feel like a fuel cut or just some misfires?

 

I am having a similar issue with my car. Unfortunately I bought mine used and dont have all the information on what has been done to it. I posted my issue about 5 days before you posted this https://www.evolutionm.net/forums/evo-engine-turbo-drivetrain/563357-slamming-surging-when-trying-accelerate.html and was wondering if you have come to any conclusions?

I have been out of town for the last couple weeks so I havent had the time to look to far into it yet, but also did a boost leak test and mine too was rock solid. I performed a compression test and that to came back good. I did notice a little oil around the fill cap but figured that was a separate issue and plan on getting a new cap and checking the PCV valve... I also order a EvoScan to see whats going on there. When I get back home next week, if I find out anything I will post it here. You know help a brotha out!

 

What are the AFR's looking like during the time it starts to break up?

E85 tends to break up if running too lean...maybe on the dyno AFR is fine, but when you hit the street they change due to different amounts of air.

 

Alright well the FP Red ended up dying on me so I put a stock 10.5 on the car. Tuned it last night on e85 once again made 18 pulls all together most being right at 400hp/400tq on 25lbs of boost. I have replaced vac lines, coolant lines are fine there is no pressure/head lift/ great leak down results. there were ZERO issues on the dyno outside of the boost controller acting weird no matter what it shows 0% WG Duty Cycle. I turned the knock sensor off and it made no difference so it is not like it is seeing knock and pulling all of the timing out. The AFRs are very conservative on the street ~11.5:1. I replaced both fuel pumps assuming that even if the pump setup is not the greatest it still worked at one time. The only thing I can come up with is the car FINALLY threw P0125, though I don't see this effecting much as the front o2 doesn't show any erratic readings and this should only give me issues with closed loop driving. This by the way is only happening at 6700-7000 RPM.

 

Had the same thing on my E5, changed plugs, cam sensor, coil packs and went over everything.

Turned out that after i placed the resistor back and plug leads issue went away. One of the plug leads resistance was out of spec but still conducting.

 

not to sound like an ***...but what?

 

so this problems still happens even if your running on WG pressure? what are your AF's at time of the problem?

 

11.5 seems a little rich. I always seemed to get occasional breakup when I tried running around ~11.5 AFR on E85.

 

Yes it was happening no matter what boost level, and the afr is fine ive run multiple cars on e85 around that same afr with no issues the car ran this way for 8 months with no issues. I fixed it tonight the issue was not in the tune at all but the clutch switch. It was engaging the nlts, turned the nlts off and the car hasn't done it again.

 

You beat me to it!!! I had this same problem and turned off the NLTS and it's fixed!