I think this is plausible!
Seriously, note your fuel tank level when this happens.
I would think that you wouldn't feel it if the tank was full....

 

Dunno what exactly it is but at least in mine it is motor-related. You can see the RPM fluctuate when it does it.

 

I get the same thing - It's not bad just noticeable and so far not a problem - to me it's almost like the torque converter wants to lock up intermittently

 

i haven't had this happen yet, but the fuel thing sounds like a possibility. When i get in my hhr in the morning and hop in i can hear the fuel moving around in the tank in the back.

 

The responders in this thread must all own HHRs with automatic transmissions. It would be interesting to see if anyone with a 5-speed stick has engine surge problems after coming to a stop.

 

Yeah, yeah, I know this is an old thread, but I was wondering if anyone ever came up with an explanation or solution? My '06 automatic does this periodically, too. It feels like it's trying to bump forward in little increments while stopped at a light. I have an Isuzu Vehicross that does this except it is one nasty little surge and not a series of them. Anyone have an update or is this a just "learn to live with it" situation?

 

There are a few other threads about the same thing. I don't remember more than that, I'll try to look.

May be a timing chain/tensioner trying to give up. Is it a 2.2L or a 2.4L?

If possible I would get the OBDii codes read before the next start the next time it happens. It might be storing a code that would go away if it does not re occur the next start.

Well, turned out a quick look at the bottom of this screen turned this one up:
https://www.chevyhhr.net/forums/prob...p-light-41325/

 

Our 2006 has done it from new - very sporadic when it occurs (I'd describe it as a mild shuttering, but the car doesn't actually move with the brake applied)
, I wouldn't worry about it.

 

Mine has done it since I have had it as well. Usually only at one stop per day. Runs perfect otherwise. I cleaned the throttle body, cleaned the MAF, changed air filter, and even spark plugs and it is still there even as of this morning. You can see the RPM gauge fluctuate up and down about 250 RPM for a total of 4 to 5 seconds then it idles fine and doesn't reoccur in the same drive cycle. I've dealt with it so long sometimes I dont notice! It HAS to be some kind of computer issues. Who knows. It isn't harming anything as far as what I can tell...... Even accelerating WHILE IT IS HAPPENING does nothing, car just takes off as normal.

 

It has something to do with the tranny or A/C.