My car is acting weird under sudden high boost (+20psi). The seems to stop pulling, makes a loud pop and the A/F ratio goes lean. The weird part is that if I ease into the higher boost as compared to going WOT the car seems fine.

On Friday I was at a track day and the car was running fine. Later during the day it had a few small shudders when I went WOT suddenly so I thought nothing of it. At the end of the track day I parked the car and did not drive until Sunday afternoon, this is when I noticed this problem. The car drove home from the track no problem at all.

Since I am running a breather filter off nipple on the valve cover I think a little bit of oil might have found it way to MAF. I did notice a little bit of oil on the drive side of the engine bay. I plan on cleaning out the MAF and changing the plugs tomorrow but I would also like some other ideas about why the car is acting this way.

The car is set to spike around 27 lbs.

Thanks

 

Did you do a boost leak test?

 

Not yet I plan on doing that as well tomorrow.

 

Also check you battery connection, my cables became loose over time and I developed a similar problem, the looser they got the worse the issue got. After a lot of trouble shooting I eventually noticed the cables were loose so I tightened them down and the problem stopped immediately.

That being said, I would check spark plugs if it's not the battery cables.

 

surge issue? maybe time for retune.

 

I'll be keeping my eyes on this thread, am also getting similar symptoms... thinking it might be something to do with a slightly bent arm on my actuator

 

Having the same symptoms, just tuned with COBB AP and when I push it to high boost, only to 24 psi, boost seems to cut out at high RPM's.

 

have had a chat to a few people, and they think it could be the gapping of the spark plugs.. it has been suggested to me to reduce it to 0.6mm and then to 0.5mm if it continues and see if this fixes it. Ill be trying this next week with my mechanic so fingers crossed it works!

Also, if you're getting sharp cuts in boost, it could be a rusted actuator... mine is more a spluttery effect hence the mis-fire in the spark plugs diagnosis

 

Leak test and check plugs