Hi all -
I drove my wifes car recently, this has happened a few times.

07 MCS Auto with 30k miles, mostly driven around down (wifes car).
Car warmed up
Happened on different tanks of gas
Always run Super
No lights/warnings on dash
Car in standard (non sport) mode
Car has had the timing chain fixes and runs pretty quiet

Symptoms:
Car is in 5th, maybe 6th gear. Press gas to slightly accelerate to avoid kick-down, I can hear a pinging sound and a slight delay/hesitation in acceleration.
If I gas it, car will kick down and accelerates fine

My questions are:
--Could this be carbon build-up related?
--HPFP related?
--Any suggestions for further diagnosis?

If it's carbon related, I'm probably due for a walnut cleaning.

Will a catch can avoid this build up in the future?

Thanks

 

Pulled in an approved MINI-protocol scanner to see if there's any fault codes present?
Have you pulled spark plugs and inspected them?

To see if you're affected by carbon build-up, you will have to remove the intake manifold and inspect the backside of the valves.

An oil catch can will help, but driving habits (like 'grandman-driving' or short trips) also play a significant part in terms of carbon build-up.

- Erik

 

Have not looked at the codes, is the dealer the only option here? I know I can get a generic ODBII reader...

If I pull the plugs what am I looking for? Oil? Signs of excess heat? Cracking?

Thanks

 

That's a start. Make sure to record BOTH the code number(s) and descriptions.

First, the electrode gap.
Second, color and overall appearance; there's several charts online with pictures on what spark plug colors mean.
And finally, yes the ceramic insulator to make sure it's intact and not cracked.

- Erik

 

Follow-up on this. I had the car in at the dealer to do the aux pump recall. I also had them checkout the car for the HPFP issue (I still have the original pump... ).

They ran a diag and found super-ping codes stored. I had them inspect and they found carbon build up on the intake valves (32k miles, 5 yrs old, wife drives and doesn't drive hard). The mechanic I talked to said he saw no other issues and was confident this was the problem.

They did a walnut blast + a reprogram of the car + the aux pump.

The cost for the service will come out to about $600, which is in line with a couple of local shops that do this. If it lasts another 30k I'll be pleased.

I pulled the plugs before going in and they looked fine.