Lose power after 4k & car kinda of bucks?

[TSiAWDMillz]

So I took my 91 TSi out for a spin the other day after it sat for about a 2 week and it will start to pull up to about 3.5k-4k then quits pulling but continues to build boost and the boos tgauge reads higher than usually? The other thing once it gets past 4k during hard acceleration it like bucks, kinda of like it is misfiring is about the best way I can describe it. You guys have any idea what is going on? The car is pretty much stock.
any help would be appreciated
Thanks,
Josh

 

[skippydog21]

Im seeing the same thing in my womens car. I will let you know if I figure it out

 

[luv2rallye]

Check the coil and plugs.

 

[EclipseTrbo420A]

how much boost areyou running ? mbc ?

 

[TSiAWDMillz]

I am running about 15psi boost with a MBC. OK now one thing that is weird or atleast to me that is weird is that only when I drive does it have these problems. If i Open the hood and rev it up to about 6k it doesn't do any thing out of the ordinary.

If I had a boost leak how would the car run?

Any help would be great
thanks,
Jsoh

 

[BoostinFool4G63]

I had a problem similar with my old 1G. I would hit 3k and it would stutter and buck big time. Turned out to be the ECU.

 

[TSiAWDMillz]

So what did you do buy a new ECU or replace the capacitors ? I was thinking about replacing the capacitors any way.

But did it happen all of a sudden? Cause I had the car out like 2 weeks ago and everything was cool the car was running strong?

the other thing is the idle is off it goes up and down but that should not effect the way the car runs should it?

Thanks for the help,
Josh

 

[EclipseTrbo420A]

I am running about 15psi boost with a MBC. OK now one thing that is weird or atleast to me that is weird is that only when I drive does it have these problems. If i Open the hood and rev it up to about 6k it doesn't do any thing out of the ordinary.

If I had a boost leak how would the car run?

Any help would be great
thanks,
Jsoh

Turn your boost down and try to drive it . I have a boost leak and my car runs ok ver verysmall one but know its there , whats your vaccume at on your boost gauge when at idle

 

[BoostinFool4G63]

So what did you do buy a new ECU or replace the capacitors ? I was thinking about replacing the capacitors any way.

But did it happen all of a sudden? Cause I had the car out like 2 weeks ago and everything was cool the car was running strong?

the other thing is the idle is off it goes up and down but that should not effect the way the car runs should it?

Thanks for the help,
Josh

I first borrowed another ecu and then i just got a new one. I didnt feel like messing with the caps. Yes it did just all of a sudden do it one day. I also had the unstable idle too come to think of it.... I would try swaping a friends in there and go from there.