I have my car in the shop right now at jerry little car shop in kent and atkins recommended them so i trust them but he is having a problem finding the issue with my car. The problem is that i will have i have boost and then i shift and the boost will begin to build again and then when i get to 6000 rpm the car sputters and then my car is usless after that. If i shift and let the rpms drop down to about 2000rpms then gun it ill have boost all the way to redline. Also if i get on it lets say in 4th gear and i left off and then get back on it i get no boost. This is such an aggrivating problem any help would be great thank you.

 

No boost gauge?

Dave

 

yeah i have a boost gauge

 

What is the boost reading when it cuts out and sputters? Is there any chance the main cat element is breaking apart?

The lack of boost and sputtering sound like different issues. Most cars when they have a boost problem don't sputter at all - they just get down to 0 psi and lack power. For the boost issue, I would change out the check valves if they haven't been changed before.

Dave

 

High RPM sputtering makes me suspect an ignition issue. How old are your spark plugs and wires?

-s-

 

But the fact that it will run to redline some of the time makes it sound less like ignition.

Have you seen cases where ignition problems won't happen each time?

Dave

 

the spark plugs and wires only have about 4000 miles on them and they are NGK

 

i know my main cat is leaking a little bit and the boost shows about 8psi when it sputters

 

what about the blow off or bypass valves? , check that.
And check turbo hoses, if you still have the original secuencial setup chech the hose that is just after the Y of the 2 turbos.
It can be the exhaust manifold gaskets too.
Or the wastegate diafragm can be too

 

I would take off the main cat and shake it around to be sure the main element hasn't broken loose. When it breaks loose it can block flow and hold down boost.

Dave