My parents have had their HHR for about a year now, absolutely no problems. Today it has started to putt and stalled/turned off at low speeds. The putting happens at random intervals and kind of shakes the vehicle a bit. It feels as if it moves the car forward a bit, maybe it's in my head.

The original owner replaced the engine less than 100000 miles ago. I asked him today if he had the problem in the past and he told me he did and the problem was the catalytic converter.

The car was involves in a accident about 2 weeks ago but it was cosmetic and didn't affect the driving of the vehicle at all. I have a video of the putting but I'm not sure how to post it here since it only lets me attach pictures.

Hopefully someone can help me out

Edit: 2006 2.2 LS
I have uploaded a video with audio to imgur
http://imgur.com/gallery/EjlAwW1

 

Welcome to the site, first I recommend having the battery load tested, the charging system tested.
Have the OBDII codes read, there might be a pending code.
Accident? Which end ? The battery is in the rear to the passenger side.
the ground connection and the underhood fuse box are up front, on the drivers side.
Check those also.

 

Hard to believe no Check Engine Light with those symptoms. If there are no codes the internet can only make wild guesses.

 

It was on the front passenger. It pushed the headlight back a bit and cracked the bumper, it was a low speed accident

 

Could’ve damaged some wires, impact could have damaged underhood fuse box , if it was loose.
Time to have a look , the alternator lives out that area front passenger side.

 

Any chance this started right after a gasoline fill-up at the cheapest gas station in town?

 

Last time I got gas was Friday 8/16 but it was at the cheapest gas in town but the problem didn't arise until yesterday.

 

Are you going to get the OBD codes read?
has the air filter been changed lately?
are you capable of doing troubleshooting and mechanical repairs?
Why would there have been a problem with the catalytic converter? What problem?

 

Just curious.
1st post says it's a 2006 LS with a 2.4. Could you even get that combo model/engine back then ?

 

I don't have codes on the dash but I will plug in my obd to see if there are any pending
Air filter has not been changed but it's a K&N filter that can be washed out.
I don't have much knowledge about cars but I am capable of learning to fix things, when I can
I'm not sure why the cat would be a problem but I described the problem to the previous owner and he told me that's what he did to fix it. I have no idea how it would be the culprit.

I went ahead and changed the sparkplugs since they were almost at 100000 miles and they were either white or black at the spark end. Also unplugged th battery during the swap. It fixed the problem for about a day but came back but less stalls and less frequent putting. The putting disappears when I'm driving but at idle it's there.