Started 2 Nights ago... Everytime I hit around 4.5k RPMs my could take a nose dive and start sputtering and my boost would quickly drop (never even makes it pass 10psi). I'm also getting a lot of back fire...I recently installed a Down Pipe and a Test Pipe, but the problem only came up 3 days after. I got a CEL a day before the probelm started. I thought it was maybe cause of the sudden warm weather, but at night I start up the car and the idle became so loppy as if I had cams...

Anyone have a solution/similar problem?

 

A complete mod list would help.

does it nose dive in every gear at 4.5k?

 

who cares what happens to sti's... thats not what hes asking. and yes it probably is fuel cut... when u do a downpipe and cat delete it raises boost levels and spools ur turbo quicker... however i dont know about the 10psi thing.... when i put my dp/tp on i got a mbc to lower the boost... also do u have an intake.... that could cause the problem also.

 

stop spoiling the board with your ignorant, annoying off-topic posting. nobody cares what you say in here, newbie.



Have you checked your afr? where are your boost peaking at?

if it's doing that around 4.5k, looks like you're pulling some major timing...

The mod list would help a lot.

looks like your afr is dropping a lot around 4.5k (running pig rich) which is normal for the evo with stock afr. That would explain the backfire.

I would also try to reset the ecu, since it maybe that your ecu went into a safe mode, limp mode.

But pull the code first to see what's going on.

 

Mod List,...

Intake
IC Upper and Lower Piping
TBE
Forge DV

No way for me to check my AFR i dont have a guage,...my boost peaks at about 10psi or so and then does a sudden nose dive and it starts sputtering...

what do you mean "pulling the code"...and how do i go about doing this?

 

mine started to do the same thing after i got done racing a z28(on a track of course). i hauled down from the high 140's and tried to hit it again and once i got back up to around 15 or 16 psi it started misfiring like crazy. it did it in every gear no matter what i did. boost would drop down to 12 psi or so. i had no idea what to do to fix it. i took it to the dealer and they fixed it. i am looking for the service right up now. hopefully i can find it.

 

i started having the same problem yesterday as the weather cooled off w/ rain. i have a TBE (catless) as my only mod. i was getting some back fire in between the 2-3 shift at just about 4K rpms yet i have no CEL's. any thoughts?

 

maybe check you plugs...might be bad...

 

My first 2 guesses would be fouled plugs or an IC pipe that came lose somewhere, especially since you have installed both lower and upper pipes. It's possible that it just occurred recently, so it doesn't matter if you didn't have this back when you first installed them. Tossing in some copper NGK BPR7ES is easy as cake, though, and will only cost about $7 total, so try that first.

 

that would be really helpful

i checked my IC piping, they're all tight and where they should be...replugged the MAF sensor, checked all my exhaust pipings for leaks...they're all fine

 

I have the same problems as you. I ve had it for a week and cant figure out what it is im trying to do everything before i have to take it to the dealer so a solution would be great.

 

Alright uhh... Reinstalled all the Stock pipes, Exhaust, Intake, and IC piping...and it still does it...

installed back the aftermarket ones and made sure they were all tight and secure...and it still does it...

Is it possible that the Down pipe+test pipe modification might have pulled it off timing?

I also don't have an AFR gauge...but does this mean i might be running really lean as well?...

 

check the gap of your plugs.

i had a similar problem, and it turned out that they were gapped to far.

 

if its backfiring its running rich, not lean. What is your vac sitting at at idle? Is your bov plugged into your intake correctly? I know when I had hks bov my intake plug fell out and started doing exactly as your describing. Make sure your intake did not come off at the turbo, if the engine takes in any air after the maf the car will not run right.

 

What if its a boost leak? What kind of Spark Plugs and Wires are you using?