Its because of the boost build up in those gears. Its not abnormal, you just need to downshift to be able to spool your turbo. Your rpms are too low to be able to spin that turbo at the demand you are asking when you floor it. The motor isnt able to "keep up" so to speak and build its rpms fast enough.

 

He said it happens in 4th and 5th gear on the interstate. It shouldnt sputter and jump in 4th gear especially at highway speed.

 

^ yes it will, if you are not above 3 grand dont stand on it. its creating compressor surge and its bad for the turbo. our engines are too big for how small the turbo is so it will create full boost at too low of an rpm for the turbo to handle. does it have an aftermarket wastegate actuator? take a pic of the turbo and post it up if you are not sure and we can help you. if it does have an aftermarket wga then that is another reason why its doing that. its call part throttle boost, or ptb, google "ptb srt 4" and read up.

 

Who doesnt like PTB and all the fluttering that goes along with it as it reaches 18psi?

 

compressor surge thats it! That phrase was escaping me at the time I was writing lol

 

Heres a video of the car smoking a little, and here is a engine bay video too. all in one.

i cant honestly describe it any better than this.

Now its doing it in third gear, when i hit around 3-4 grand the turbo feels like its spooling up and blowing off too quickly. and the car jumps and sputters. even at half throttle. Not stomping it. Im going to try and get a video of it soon.

http://www.youtube.com/watch?v=q984nClmv20

There is the video of the exhaust smoking and a engine shot.
and it has a greddy BOV

 

hard to tell from the video, but whats that orange thing above the turbo intake? Is it a boost controller?

 

Your wastegate is stock it is not a AGP and wrong color to be a Forward Motion. And I cant tell if that is a boost controller or not looks like one. But does your car smoke when you first start it up or does it do it all the time even when it is warm? Seems as if your turbo seals are leaking. If it does it cold that is kind of normal because the valve seals leak a bit onto the pistons overnight but once it is warm it should do it like that.

 

it does it normally on startup. not after its hot it normally doesnt.

and here is a in car video of the turbo acting up,

http://www.youtube.com/watch?v=4FU9slTYvFU

 

Why is your check engine light on? And yea that doesnt sound right at all. Not compressor surge that is for sure.