Evo 8 power loss at low rpm's
 

Not sure if anyone has ran into this issue but not sure what else to do hope someone can give me some ideas or clues on where to look. It has been stock all her life never been tuned till recent. So the issue I'm running into is that from idle to about 3k she falls on her face literally during acceleration! like a sudden loss of power then she "wakes up" Its almost feels like a miss fire/bogging for a split second then she goes back to normal :confused: and she didn't hiccup on the dyno :( I figured the problem was fixed. I installed all the parts listed below and headed to a reputable tune shop here in Los Angeles to get all my parts to work together. Other that the miss fires I was getting from a faulty coil pack my tune went without issues after replacing both coil packs/wires/plugs. I did have my stock plastic 8 bov and they recommended to get a oem 9 metal bov (which I did order) and the next day she did it again!

Here are my mods:
2004 Evo 8 120k miles
Evo 9 turbo w/02 dump new gasket/downpipe gasket
Turbo back catless full 3"
ETS upper/Lower IC pipes and ETS intake (MAF)
GrimmSpeed boost controller
Mishimoto IC
Walbro 255 fp
New 02 sensor on the 02 dump

I'm still running stock fuel injectors which I will be replacing when I return for a dual map e85 tune. I'm sure it would of shown on the tune if my infectors where bad right? the dam plastic bov was holding boost as well the tuner was pretty surprised lol. Could it be the IAC? fuel injectors? don't know what would cause the car to randomly fall on its face during acceleration randomly :confused::confused:

Any help would be great thanks everyone!

I don't think it you iac because your car is not stalling. It sound like your plug are getting fouled. What kind plug do run? Check for boost leak.

BR8EIX NGK
I'll try to do a boost leak and see. I did replace all the ic piping and intercooler along with a new intake. What crazy is that it runs great then it feels like you slam the break for a split second then gets back to normal! Plugs have been on for only a couple weeks. She did stall once at a light

also to note it did this before any mods and after installing all my mods and tuning :(( thing is that its not a consistent issue and not throwing any cels.

Boost leak test?

Couple of thoughts:

First things first, definitely do a boost leak check like everyone else has said, may be a very simple fix.

If your IAC was bad you would most likely see some "hunting" at idle, as in the RPMs would be all over the place (500-2500 when mine was bad). IF it is a bad IAC, DO NOT BUY ANYTHING OTHER THAN OEM. Nobody has managed to find an aftermarket one that works consistently.
Also I don't think this would cause what you are experiencing.

Do you have an Aftermarket AFR gauge? If you do, check to see if it goes lean/rich when it "bogs"

Definitely change that BOV out, I experienced a similar issue with a bad BOV.

Let us know what works!
Good Luck!

I don't run a AF gauge but definitely on the list of things to do and yeah that's a great idea to see what is happening there. Ill do the boost leak check and get a OEM IVC since mine has never been replaced and have about 120K miles now thanks for the ideas! i'll keep this thread updated.

Is your motor stock? If yes you shouldn't be running BR8IEX they are to way to cold for a stock motor. My motor don't perform as well with the iridium plug but with the copper one the result are amazing! I have to replace my plug more often but the performance is always there. Check the color of your plug ( white, black, a lot deposit) let us know

Yes it's a stock block just bolt on's what plugs do you run? before my tune they where white and running BPR7ES and the plugs where white but I went in un-tuned with a few aftermarket parts. I was miss firing like a motha at high rpm's and realized my coil packs where bad. So new coils went in along with those new plugs and ran great! just she still falls on her face with the old plugs and the new ones :( im in search for a boost leak kit and I did follow all the vacuum lines to make sure one didn't pop off and also ran the ones under the intake manifold everything checks out. I'll check the plugs and see if they are white or black. Curious on the plugs your running tho there are so many threads on what plugs to use I think i've ran just about all the ones the car will fit :drink:

NGK bpr7es they great for about 5000 miles and my boost spike to 26 psi. I'm currently untune b/c of the turbo I add and I'm planning to switch cam going to s2. Because of all that the car is running a little bit lean so I am gentle with it till it tune. If you still are misfire after boost leak check your coil and the boot of coil.

Es= copper
IX= iridium which last a lot longer than copper.

What is your hp at the wheel?

Copper Plugs:

Stock/Bolt-Ons - BPR7ES

Bolt-Ons/Bigger Turbo + High Boost - BPR8ES

Iridium Plugs:

Stock/Bolt-Ons - BPR7EIX

Bolt-Ons/Bigger Turbo + High Boost - BPR8EIX

Link...

http://www.extremepsi.com/store/cust...pe=Spark+Plugs

I finally have a day off! Im going to check out the plugs/color and install my 9 bov and im waiting for the icv to arrive those things aren't cheap for oem. Ill keep the thread updated with any finds thanks everyone for the tips