sputtering out at 4200 rpm

[Cassanova122407]

hi guys my problem is that my car runs beautiful till i hit 4200 rpm then it cuts out and boggs down and will not past 4500 rpm it keeps bucking and sputtering and will not go any faster it also smokes like a b##ch when this occures ..
I have brand new bpr6es's gapped to .028 and newer wires also have done countless leak tests only leak is tb shaft seals and it is not that bad I can still hit 18 psi until 4200 rpm mark...

Any help is greatly appreciated thank you all in advance...


(mod list is up to date)

 

[tomlaw]

What are you using for tuning? I did not see it listed in your parts list.

Also are you getting any knock?

What are your AFR's looking like?

Black smoke or blue smoke coming from the exhaust?

I had a similar problem where I was unable to boost past 15psi, then 10 psi, then 5 psi as time went on and could not make it past a certain rpm accompanied with lots of sputtering. I checked for boost leaks, changed the MAF, messed around with the SAFC 2, checked wiring and ECU and still no luck (my plugs were new and properly gapped). Well after taking the car apart like over a year later I found out my wastegate had seized on my small ported 16g. I was running super rich at 3500-4000 rpm and could barely get past 60 mph on the freeway. There was lots of sputtering and black smoke with the occasional fireball from the tail pipe.

My advice to you is check the wastegate if your car is running rich and also the aforementioned MAF, tuning device, etc.

 

[Cassanova122407]

no tuning as of yet,wastegate was shot couldn't even boost swapped that one out now boostin great but now this...

 

[92AWDHX40]

Boost leak test, turbo seals maybe.

 

[DsmDanny98]

No tune? I think that might be your issue....

 

[starktech1]

your running 18 psi without any tuning at all? Or did a previous owner do work to it that you dont know about..

 

[Cassanova122407]

nope i have all paperwork from original date of purchase i have been working with it for about 5 months now on a very limited budget and it gets better everytime but i am stumped on this issue it kinda feels like fuel cut but i know for sure it is not, no matter how much gas i give it is hits that mark and boggs and sputters out...
if it is any help it also does it when i free rev it but it does it then at 5500 rpm.

 

[DSMBlake]

just a thought to check ,i had a issue with my coil, testing it to oem spec.found it to be bad,
i couldnt rev over 5k.

 

[Cassanova122407]

thank you i will check coil this weekend is there anything else i should be concerened with?

 

[niddydsm]

Check your MAS as well

 

[tcouty87]

2nd what dsmblake said. Mine would stop at 3800. Get it up to op temps n do an ohm yest on the primary n secondary wiring. One spark plug may look different than the rest also if i've been driving it like this for awhile

 

[Cassanova122407]

update problem seems to be fixed i exhausted funds buying everything brand new and still no luck...
I have fixed the problem after performing a maf hack apperantly my car was starving for air idk why but it worked so thank you guys for all the help.