First off it’s a 2011 2.4L. It has 157,000 miles on it. Here is what’s been done at 120,000 miles.
spark plugs
Airfilter
o2 sensors
Timing chain.
140,000 miles MAF was showing voltage problems so got it replaced and has been great.
Have been chasing a random large evap leak that would show up and disappear often. It was the purge valve under the hood working sometimes.
Now in the past week first thing in the morning after the HHR has been sitting. I drive it a 1/8 a mile and all a sudden from 20-45mph it bucks pretty good and struggles. Will do it for maybe a mile after then never again until 8-9 hrs later after sitting... No SES lights.
Anyone have any guesses? Oldblue was also trying to help me figure this out

 

Pull the codes and see if anything points to the issue.
You say no SES lights. Guessing that means Service Engine Soon ?

 

I’m leaning towards dirty fuel and or fuel injectors, to refresh my memory, you cleaned the throttle body?

 

Maybe Ignition module or loose ground(s).
Can you rev the engine in neutral when it acts up?
Try to isolate mechanical, ignition, or computer issue.
No SES points me to my maybes.

 

FWIW. The HHR has no Service Engine Soon (SES) light. It does have some other Service warnings though.
---Just so we're talking about the same thing here---

 

CEL, SES, MIL All names for the light that tells you there are emissions codes.

 

Only code stored was for evap purge valve under hood which is gone with new part. I haven’t looked at the throttlebody since 140,000 when I found out the MAF was bad and throttlebody looked good. Once in a blue moon I get gas at a BP but before this past week I think I got it at Speedway where we always go and guess it could be bad gas..

Only difference was at speedway the pump only had 87-93. I use 89 and it was out so filled tank up with 93. The other day I was almost empty and that’s when I went to BP and filled it up using 89. Maybe the 93 bothered something? I also but the 89 from BP at the same time in my riding mower and ran it for a hr with no issues.

Do the fuel injector cleaners you add to the gas really do anything? I read where it’s nothing different then what’s already in the gas at the pump?

 

When it acts up I’m driving so don’t want to click it into neutral and rev it as can’t see that being great for the transmission?

 

Switch back to the 89 octane, clean the throttle plate, remember do not move that plate, just spray the throttle body cleaner on it. You can remove the 4 bolts that hold it to the intake manifold, lift it off and spray the engine side.

 

Okay will do. It acted great all day today and think I will wait till I have to fill it up again and see if same thing happens.