Hey everyone,
My car has been acting up once again.

So, sometimes when I put the car into neutral (for instance stop and go traffic), the car's RPMS drop very low (lower than a 100 RPMS) or wants to stall. This also happens when I put the car from 2nd to third or 4th to fifth (however in the higher gears, it just drops to low RPMS, it doesnt stall)

And when boosting on WOT, the car kind of like "skips a beat" or jolts/ bogs down. I had a similar problem to this before I put in new spark plugs, but that was during any throttle, this issue occurs only at WOT. ( I'll see if I have it on dashcam footage)

My car was previously tuned and the tuner saw this issue aswell, and they claimed that it was a flap inside the intake tube that was causing this. They said they tried removing it, and removed most of it, but I'm still having that issue.

Im not saying they're wrong, I am just looking for more opinions because I only want to spend the money on a new intake if I have to.

I was possibly thinking it could be spark plug wires or maybe coilpack because i recently replaced spark plugs (less than 2,000 miles ago)

I'm pretty sure that these problems are related, so if anyone has anything that could possibly help, that would be awesome! Thanks!

 

WOT sounds like plug blowout. What are they gaped at?

Stalling sounds like a tune issue/ boost leak/bov.

New plugs, gaped correct, and a boost leak test I would do first.

I have no clue what intake "flap" they are referring to, or what they removed. Is this an evo shop?

Do you have a wideband? What's it read when you let off?

 

They were ngk Br7es plugs gapped at . 026, less than 2,000 miles ago. It is a shop that does work on evos. And I do not have a wideband.
when going to neutral and it stalls, I sometimes hear a flutter, so there might be something leaking.
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Do you have an aftermarket BOV on the car?

Do you still have the stock intake tube?

MAF EVO's especially VIII's hate either unless some proper MAF scaling and tuning are performed. I'd find someone selling a stock intake tube and put that back on the car first

 

It's an evo 8 with a Evo 9 BOV, the car came with a K&N typhoon Intake system

 

Which is arguably the worst intake set up ever made for the EVO CT9A platform.

Search on here for old threads regarding that intake system. Grab a stock intake tube, put it on the car with a MAF adapter and open element filter if you want and I bet your cars drivability gets better with no loss of power at all

 

I had WOT breakup (similar to what you described) when I increased the boost on the stock turbo to 30psi at 4700, had to close the gap to .022. When I upgraded to FP red and ran 30psi till redline I again had to close the gap to something closer to .019 to eliminate breakup.

At .026 you may need to close the gap a bit if indeed what you're experiencing is breakup and not something else

 

OK, so heres a vid of the bogging on WOT. Turn up the volume and listen. Also, sorry about the high pitch screech, i think my car broke the mic

Watch between the times of 0:00 to 0:05 and 1:24 to 1:28 - The "Cut out" happens at 3 and 1:27 seconds.

 

I’m leaning towards that intake/maf. And whatever “flap” they removed. Throw a different intake on and check it out.

Also, IMO .26 is too big for anything but a bone stock car. I’m at .22. Any bigger and I always get spark blowout. I would still throw plugs in it.

 

There's a proper way to set up the idle speed ........as per the service manual.

That's the first step.


If you've done it wrong or not done it...........then stalling is a possibility even with an unmodified car.

 

Yea, I was looking at older threads and some had similar setups to me and they were gapped at. . 26 - my cars running 331WHP at 22 psi. So, should order some new plugs and change them to. 22?

 

I'd try .24 first.

Some cars get away with it. Some don't. See above where someone needed .19 lol.

Obviously the goal is to have the largest gap without blowout. Throw some coppers in, gap them to .24 and run a WOT test. IF it still occurs, .22, if it still occurs, then it's most likely not spark blowout. I would suggest a wide band reading at that point, almost sounds like a mini fuel cut.

Right said Fred is correct with the idle adjustment, but it would have to have been messed with prior to have such a large effect IMO. Something worth looking into.

Has the car always done this?

 

yikes, that looks like a violent jerk. I've never experienced breakup with a loss in power like that, only very brief hiccups that can be heard but not necessarily felt.

 

Yea, sometime it actually hurts.. I was once merging onto the highway where I had to floor it, and since it jerks, I got a bruise across my chest because of the seatbelt. Its hard to explain the motion of the car during the hiccup

 

That sounds exactly like fuel cut - like driving into a brick wall. I can't imagine this is breakup from improper spark gap, but I'll let someone with more experience make that assertion.

Edit: Do you have a boost gauge? is it possible you're over-boosting and ECU is seeing crazy load % and cutting fuel?