Hello,

So this has been an intermittent problem on my car for a while now, during summer when it gets really hot here in So Cal, my 2013 CMS All4 (93,000 miles) will struggle occasionally going up a grade for extended periods of time, no jerking, no stumbling, just a sudden loss of power and acceleration. It will kind of hold it's speed and very gradually start to go slower, almost like there is a boost leak and it stopped making pressure. No warning light of any kind. However I have monitored boost with a bluetooth OBD module in the past trying to catch it, and the couple times I have it does not show a loss in boost pressure. Checked the intake tract for leaks, charge piping, nothing.

The only code that has been thrown on this car is a P0171 (system lean bank 1), I have checked for vacuum leaks and found nothing unless it is potentially the PCV in the valve cover. Leads me to think it is a fueling issue but it seems inconsistent with a lot of the failing HPFP symptoms but I could definitely be wrong there. The price of that part makes me wince and I don't want to throw it at the car and have that not be the case.

It seems to only happen when it's 90+ degrees F outside, and I have had a temp warning on one occasion, but it promptly went away and I have never seen it again.

Could this be related to my cooling system? I would think it would throw a code if the thermostat was stuck open. HPFP? Ignition Coils? PCV/valve cover?

This has not happened in over 4 months and never happens under normal driving, but we had a hot day here and was going up a large freeway grade and it came back to remind me it was still there.

Any help is appreciated. Thank you.

 

Have you found out what this is? Mine was having sudden drops in power... it was a crack on the intake at the turbo. I patched that and the car ran so much better over all. It just started doing the lose power, kinda drop thing again now that its been over 85+ degrees F... have to check my patch on the intake.