@Osgar , the code you have is a good start but we all will just be throwing darts without a solid base line of info:
Year and model?
Mileage?
Any other set or pending codes?
Anything changed, modded or replaced recently prior the the code being thrown?
if its a GXP the stock charge tubing (some rubber, some aluminum) needs to be thoroughly inspected.
The connecting points of the charge air piping are prone to leaks, the intercooler (CAC) is a common source of leaks caused by running over parking curbs all the way to just regular good old fashioned failing.
The rubber throttle body hose can be a source of splits or cracks, etc etc.
The small rubber o-rings on the map and maf sensors can fail or not fully seat and thus leak.
The intake manifold is attached at a low torque number by specification and can be a source of leaks from bolts loosening.
You can use a can of starter fluid near these connections to see if a spritz of the fluid at a connection point causes an increase in idle, you can get soapy water and spray the connections looking for air bubbles.
The nipple on the air intake hose coming from the air box can crack and leak.
The multiple vacuum lines to the turbo and solenoid for it can leak..
I could go on however i think you get the point.
The cheapest thing you can do is a thorough, piece by piece, connection by connection examination of the charge air and vacuum system.
It takes patience and time but it wont cost you anything to do the inspection, and may save you the heartache of throwing parts at the problem in an attempt to hopefully hit the bullseye.
I speak from experience.
In my case aside from discovering a couple micro leaks, i ended up discovering a loose washer that had made it’s way into the intake side of the head and jammed itself a few millimeters from one of the intake valves.
I spent many weekends ordering a part i thought was the problem, waiting for the part, then installing it with fingers crossed to no avail.
I finally followed everyone’s advice here and just set aside two days with a buddy and started at the air box, took one part off at a time, thoroughly inspected each part and worked my way through the charge air system. I got to the throttle body and verified all the parts were solid and t-bolts were tight. Still no love. Then i remembered about our DI engines being prone to carbon buildup, so i finished the job and removed the intake manifold and finally found the problem, the washer jammed into the intake port on the head.
Who would have guessed that in a million years?
The moral of the story (at least for me) was to take my time and thoroughly work through the problem, step by step. The inspection cost nothing but time and i found an almost impossible to diagnose problem before it damaged the engine. However i wasted a lot of time and money throwing parts at the problem before i “surrendered” to the process of “diagnose and inspect before fix”.
Best of luck to you!
