I tried searching the forums but I am not sure which keywords to use for this one.
There are NO fault lights, everything seems to be running fine...but

When stopping at lights in city driving, having come to a stop, it starts surging or chugging slightly. The needle on the rpm moves a few hundred up and down. If I put it in neutral, it goes away.

Is this something to do with my idle control, or transmission, or what?
I am not sure where to start looking.

Thanks

 

Are you stock or tuned? Might be bad gas or maf sensor

 

My bet is he is going to need to replace one of the soleniods soon.

This thread could help:
https://www.chevyhhr.net/forums/how-tutorial-library-21/camshaft-position-actuator-solenoid-valve-replacement-w-pics-p0010-11-p0013-14-a-28779/

It may not seem you have the same indications yet, but I'd bet you will.

 

sounds like an engine drivability problem more then a trans problem.The engine light may not be on but there could still be a code in the system.

 

Scoot by your local auto parts store and have them "pull the codes", Lucky is on target in thinking there may be stored trouble codes.

If any come up, post them here.

Also, how many miles are on your HHR?

 

Ours has done this from day 1. We bought it in '08 with 8k on it and it was still under warranty. I took it in and they could easily duplicate the issue but could not find a cause. They removed the transmission pan to have a look at it, and as a result changed the fluid. The issue went away for a while but eventually came back. We have 95k on it now and it still does this. Other wise the transmission seems fine.

 

The car is not modified as far as I know. At least I have not modified it.

As for the solenoids, I have already replaced the cam position solenoids and sensors.

Before I found you wonderful people here in the forums I took the car to a dealer and told them to exchange the transmission fluid. You know, the machine that supposedly evacuates all the old fluid. They told me "the fluid was a little burnt, but not the worst he has seen." I dont really know what that means.

I am familiar with the "pulling the codes" activity, as I did that a few times dealing with the solenoids. I think that is a good idea, I will go check to see if there are any "stored" codes. I did not know it would do that.

Oh and btw, my key fob remote went out yesterday. Changed the battery, and no luck. I am a bit frustrated because this thing is only about 6 months old. Bought from new from ebay. I guess I need to buy OEM?

Thanks all for your replies.

 

Oh and I also wonder about the relation between the brakes and the transmission. Because when you start up, you need to apply the brakes to put the auto tranny in gear, right. Well, there seems to be some sort of lock out that is deactivated when you apply the brakes, what is that called?
Can it be bled? Or is it even fluid driven?
I mention this because sometimes I have to press on the brakes and jiggle the shifter to get it to unlock.

Could this have anything to do with having brakes on at a stop light, and the car running rough?

 

That's called the "Brake Transmission Shift Interlock", it's an electronically controlled solenoid in the gear shift mechanism itself. If you have good ears, and your radio is turned down or off, you can usually hear it "click or snap" when you depress the brake pedal if you're in Park.

The solenoids can fail and get stubborn at times, here's a good thread on the BTSI....

https://www.chevyhhr.net/forums/how-tutorial-library-21/shift-inter-lock-repair-delete-39229/

Because of the rough running and "chuggle" as GM calls it, have the codes pulled when you can and post them up, otherwise...we're kind of shooting blind.

HHR's are pretty predictable in their behavior and quirks, but without trouble codes to get you aimed in the proper direction, time and money will get wasted chasing Problem A when it's really Problem B all along.

 

No.

The interlock is kind of complicated, but all switches and relays. There is a switch on the brake and a switch in the shifter and a couple of relays to lock out the shifter and the key cylinder.