fall in turbopressure and rpm for a sec ...engine breake....

[leriksso]

I have a Saab 9-5 Aero SC 2008, Aut,  MapTune step 2,

Have a confusing problem with the car so far nobody has been able to solve. Just want to hear if there is anyone who may have an idea what to do or what it can be.

When I drive and take the foot of the accelerator pedal falls turbo boost pressure, and the rpm of the engine. It feels as if it will stop and the engine braking, but as fast as it comes, just as quickly disappear. It acts like something off the ignition, and in a second.
"The engine holding it's breath for a sec...almust" 

Does anyone have an idea? or better yet know what it is. It does not generate any error codes, there is no leakage what we can see / hear.
It does not happen regularly, but more if I go slowly and take the foot off.

Would be nice to get an explanation when it is hard work to go at full throttle all the time  lol

And BTW sorry for my broken English as well.

[sgould]

Welcome!

Your English is fine !  I can understand what you mean, even if I do not know how to solve the problem.

The only time that I have had any problems like this while driving was when my crankshaft position sensor failed.  You can only check resistance on this.  The connector is the blue one in the group of three next to the throttle body.  The resistance should be between 770 ohms and 950 ohms. There are three pins.  Only two should give a resistance.

The only other thing I can think of is that one of the big rubber hoses on the intercooler is collapsing on overrun.

Has this only happened since you have had the Maptun?  Are all the parts from Maptun?  Or did you put your own exhaust and air filter on the car and just use the Maptun software?

[leriksso]

Hi and THX,

Well it seem I have some work to do in this weekend

I experienced it before MapTune software instalerades, but just very occasionally. Now it's more common that it is incurred.
There are 3 "MapTun downpipe and race catalytic converter, MapTun sports Air filter, but the rear part of the exhaust system is 2.5 "(Speedparts).

crankshaft position sensor, I will examine that and also those big rubber hoses on the intercooler

HUGE THANKS

[Max Headroom]

Welcome to the forum Leriksso! Hope you get it fixed soon!