A friend of mine just bought a 996TT with an ECU flash and after driving it around for a week, it has developed a problem. It still pushes 1 bar of boost down low, but in the midrange boost drops to .5-.6 bar before building back up to 1 bar near redline.

Any ideas as to what's wrong?

Thanks.

 

It could be a sticky waste gate or diverter valve .

 

If he's in CT, I can help him out. PM me.

 

Did he upgrade diverter's at the time of the Flash?

 

when were the plugs last changed?

 

You dont mention what type of driveability problem this boost loss is creating. Does it fall on its face?? Does it break up and start to miss??

Both questions asked above are very relevant, dirverter valves replaced?? Plugs replaced?? Either of these can play a part in this issue, if its breaking up my experience says plugs. If its falling on its face it could be the dv's, id replace those either way if they are still factory parts.

 

Change the DV's first, its pretty simple and an easy DIY, if that fails then change the plugs, they need to be done anyways.Its possible to DIY, but if its your first time you should set aside at least 4 hours........at least

 

It is possible that you've run into a fuel quality issue. Before throwing any parts at the vehicle, it wouldn't be a bad idea to run the tank low and fill up with known good Premium fuel. If the DME is picking up knock, it may be making numerous adjustments around peak torque to calm things down.