Ah, yes, It’s a 2010, isn’t it? Well, might still be useful for future reference for someone without RPD.

Also, shoulda mentioned trying some racing fuel. Although hot carbon might still preignite the fuel, detonation is less likely.

 

Its been a few weeks since I updated this but I was on vacation at the end of August and then been busy catching up with work since. But unfortunately the issue continues at similar frequencies.

I checked for codes and there are none.
I pulled all the spark plugs and all are AC Delco Iridium 41-108 and the condition of all 4 looks good.
However the ignition coils are not AC Delco. They are Autozone Duralast. They have been in the car for about 20k miles
I set the RPD to Spark Advance and noted the following when the issue arises. Spark advance will be at about +20 when lack of power issue is occurring. But after the pedal flick and full power is instantly restored, the spark advance will be at about +5. The only time I will see a negative (-) spark advance is during the warm up after a cold start.

Any ideas or suggestions what to do next?

Rich

 

Get rid of the AZ coils!

 

I wonder if this could be a bad throttle position sensor.

 

I am thinking this also.
I had problems with the Duralast Purge Valve. Switched it out to AC Delco and problem was resolved. Duralast seems to have problems with their electronics.
What are the recommended coils?

 

How would I test this? Is it something that can be cleaned?

 

IDK how it works. I was fishing for someone with more experience with that system than I have. You could look into the price of a new part. But I don’t even know if it could be the sensor at the pedal or at the throttle body. I just think if flicking the throttle changes the behavior, then a mechanically sticking sensor is at least plausible. If no codes, I would lean toward the pedal sensor, cuz how’s the ECM supposed to know what yer foot is really doing?

 

A dirty throttle body is more likely. Let’s not load the parts cannon!!

 

I agree. A sticky butterfly should generate a code, but I dunno how the sensor works. I went scrolling up to see if cleaning the TB had already been done, got interrupted, and just now came back.

 

I appears that this issue has been corrected and it was the sensors at the gas pedal (accelerator). Repaired it at $0 cost.

I kept fishing around the internet for issues similar to mine for HHRs but then widened it to other Chevy products. I found a video on someone repairing 2008 Impala that had a similar issue with partial power at various intervals which driving. They replaced the entire gas pedal part. But before I did that I figured let me just take it apart and see what we got. The side of the pedal unit has 5 screws which allows you to open it up. There were 4 contacts which were very dirty and only need to be cleaned up. I used a pencil eraser cleaned them up and then used very fine sand paper to just slightly rub on the bushings which rub on the contacts. Put it all back together and after a week of driving, no issues.