jay loukakis

stated gatting this code running lean, thought it was because of my new modified CGS intake, went back to useing premium gas now I never see the code, from now on I will only ues the premium, my HHr is an 2006 2lt, 2.4 engine, never had this code before, have filled up 4 tanks full. a lesson learned.

Greybeard999

The 2.4L does like it's premium....

JoeR

Fuel octane won't cause a P0171 code, which is lean.

The likely causes are either:

1. an intake leak

or

2. your homemade intake

Why? The MAF calibration is done for the stock intake, which means that the signal (in Hz) is converted to an air mass value. If this is not correct and computer corrections get beyond a certain point, fueling will be off and the code triggered.

I think your intake looks cool , but a tune may be needed to get the MAF calibration in order.

jay loukakis

I had the ECM programed when I had the CGS intake there wa 21 updates, the code only showed several times over 2 days not again.

Zagohhr

Also clogged injectors cause this code. I had this code about 6 month ago. I changed spark plugs, tons of fuel additives, and nothing... Just replacing the #2 & #3 Injectors solved this issue for me.

Tikker

See TSB noted below in the Service issues forum.
Chevymngr posted lists of TSB's, see item #60 (last item page 6),

08-06-04-001b

My dealer just replaced my injectors, as a good faith gesture. A really good faith gesture in my opinion. I took a copy of the TSB with me when they did they're own diagnostic.

jay loukakis

I took my modifiedn CGS intake and 1 of the screws was loose MAF sensor, I took it off to repaint it.

Lucky

If your code returns check the fuel pressure I have seen the fuel regulator fail with low fuel pressure. the car still runs fairly well but will set codes for lean. when you check fuel pressure with the engine running shut off engine and see if fuel pressure drops to 0 psi then the regulator has failed.