p0068 Code at top of RPM Band

**ADrugDealer** · 09-25-2013

So car runs great in low RPM and under normal driving conditions and even under lightly spirited driving; however, when I go wot, right before I hit 6250RPM (shift point), the car goes into limp home, with no throttle response at all. DIC says "Check traction control" "Check abs" "reduced engine power" and the code P0068 is thrown.

I used my aeroforced to log the event, Maf HZ hit 11025hz (Lq4 maf), 0* KR. 6200ish RPM, 186* Coolent, normal conditions, minus the whole limp home part.

Car is an 04 GTP w/ headers, XP Cam, E85, ZZP full stack IC, 2.8SC pulley, LQ4 maf.

I have a mini AFC sitting at home NOT INSTALLED (6 hours away, I'm at college now, but can get it sent to be fairly easily).

Any hints?

**Scottydoggs** · 09-25-2013

heres the code, and what to look for/check over. looks like it could be a bunch of things. http://engine-codes.com/p0068_pontiac.html

**ADrugDealer** · 09-25-2013

Im going to check the TPS next, what does the lq4 maf max out at?

EDIT: 11500hz got it

**Seachicken** · 09-25-2013

this is what my scanner says about that code.

p0068 Throttle body Airflow Performance

DTC sets when the PCM detects a calculated airflow rate more than expected. The PCM detects that the throttle position and indicated engine load do not correspond with the expected load and throttle position. If any intermittent DTC's set, repair those first.

Inspect the vacuum hoses for any splits, kinks, and proper connections, along with air leaks at throttle body mounting area and intake manifold sealing surfaces. Inspect the throttle body for any loose or damaged throttle blade, broken throttle shaft, drive mechanism damage. If ok, suspect throttle body assembly.

hope that helps

**ADrugDealer** · 09-25-2013

I honestly think I am somehow maxing the maf. It drives fine all the time except when I hit the top of my rpm band. I am going to check the vacuum lines though

**Scottydoggs** · 09-25-2013

maybe just cleaning the TB and its sensors will clear this up.

**ADrugDealer** · 09-25-2013

Will try that tomorrow as well! Thanks for the advice

**Fivefingerdeathpunch** · 09-25-2013

Reduce shift point to 6,000??

Because I bet the motor really spins to 6400 before it really shifts.

**Seachicken** · 09-25-2013

Originally Posted by Adecker

I honestly think I am somehow maxing the maf. It drives fine all the time except when I hit the top of my rpm band. I am going to check the vacuum lines though

my scanner asks you to look for vacuum leaks (unmetered air)
if you out flow the maf your engine would get unmetered air.

what are you scanning with? does it take frames fast enough for you to see the full picture?

edit: whoops you said aeroforce. does it have a good processor? never seen one in person.

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