So I just bought my Evo a couple of months ago and everything was good until the other day. I was driving under boost for a few seconds and it was almost like I hit fuel cut. Something seemed like it popped and now everytime I go under boost too long it does this. I checked to see if any couplers or anything are loose but everything looks good. I don't think it's a boost leak. What could it be. The car never did this before.

 

Has the car been tuned?What kind of boost you running.

 

you did hit fuel cut do to boost creep
do you have stock or aftermarket o2 housing?
get the car tuned and it will remove it as i have heard from other ppl

my car does the same even more as it gets colder

 

As it gets colder this becomes more common. Do you know what boost you're running? Did it suddenly get colder where you're at?

 

Mods? Boost? Sure you checked all your intake hoses? Will the car still run and idle, just not able to get into boost?

 

Yes it has gotten a little colder but I don't think that would have done it. I have since however gotten my Stage 3 Clutch put in. Could this be a reason? Also, I have been messing with my TurboXS MBC. Not sure exactly where I want it set at. Any suggestions?

 

As for Mods just a HKS FMIC with Piping, Greddy BOV, SPEC stage 3 clutch, and I just installed my grounding kit. Boost is set at around 16psi.

 

So you are adjusting your boost without tuning it? Give us a list of your mods please. Also, have you ever at any time had your car tuned? Also, when you say your car feels like it hits fuel cut after you are in boost for a while, do the rpms go up and the acceleration stop? Im trying to rule out the clutch, but it sounds like you are fuel cutting from overboost situation from juicing your boost knob.

 

16psi on the stock turbo without an upgraded exhaust? I'm thinking your restricted exhaust is spiking the turbo and causing fuel cut.

 

My mistake man. I do have an upgraded exhaust. But, no I have no personally gotten the car tuned since I have had it. Not sure about the guy before me. So I shouldn't touch the MBC unless I'm getting it tuned?

 

Correct. If you change your boost, you are going to want to get it tuned. Dont think of it as a power knob. Think of it more as just one of the other components to making your engine run efficient and safe, just like you wouldn't go adding more fuel or timing advance without logging a dozen runs and making adjustments.

 

Ok well I guess I really messed up then because now I notice my boost gauge maxing out when I do this. I guess it was from me messing with the MBC. Now what do I do?

 

Anyone?

 

Maxing out your boost is never good, you could have been running lean in a cylinder or maybe had misfire.

 

I would turn it all the way down until you get a tune. Do a compression test and check your spark plugs asap.