I have a 2006 LT and I have been having the idle act up recentlymbut only when I come to a stop. It runs great great when it moves, but once I brake, the revs go from about 900 to about 500 and then go right back to about 900. It sometimes does it once or twice and then stays constant at about 900 but other times it just keeps going up and down until I give it gas. The first couple of times it happened, I had my sound system going pulling about 2000watts without a cap, so I figured it was that and dismissed the issue since my headlights would dim on every bass note. Recently, due to a totally separate issue, I disconnecting my whole system and don't have my radio going and I'vennoticed it started doing it again(without the dimming headlights) due to my other issue, I've replaced my battery, air filter, spark plugs and have ran injector cleaner and gas anti freeze through it. I found an older thread that suggested the spark plugs(that are only three weeks old)and thats all the thread related to it. Does anyone have any input on this???

On an added note, I have about 125,000 miles on it if that helps.

 

Maybe the throttle body needs cleaning, similar symptoms.

 

X 2 Throttle body jumped to mind first here too, I'd look into cleaning it and go from there.

 

x3 its a good place to start and a cheap repair.

 

Could also be the Idle speed motor acting up.

 

No such thing on any HHR.

Agree with the other recommendations to clean the throttle body.

 

HHR doesn't have one. My 2003 Impala does. The pintle cap on those usually get caked with crap and needs cleaning. Just did mine. You have to be careful putting the AIC Motor back in because you have to c a r f u l l y put the pintle slightly back before remounting the sensor or you can damage it.

I would think in your case clean the MAP and Clean the throttle body. Also check for any pending codes leading to the throttle body. With all that mileage it could be starting to fail.

My wife 05 Cobalt had the same type issue 2 weeks after we bought it used. Codes started pending pointing towards the throttle body. Dealer was great-especially when I told them the codes and stated to them that the car was "going into reduced power". They checked out what I told them and in less than 40 minutes I was out the door at no charge.

By the way the Cobalt only had 53,000 on it when the TB went.

 

Thanks alot guys. Great advice. I did get the "Power reduced" message a few weeks back, that was the other "issue" I had and replaced al the above mentioned parts. But now with this, I think I'll have to bite the bullet and go ahead and replace the TB. I'll try cleaning it first to see how it runs for a few months but ultimately I think I'll replace the TB as routine maintenance. Thanks alot, I'll keep posted on how it goes after cleaning.

 

#PIC4125B: Reduced Power Message Or Long Crank No Start On The First Key Crank - keywords 2.2 2.2L 2.4 2.4L battery cooling crankshaft dead DTC drain draw engine extended fan hard harness key lamp L61 LE5 light - (Nov 17, 2008)


Subject: Reduced Power Message or Long Crank, No Start On The First Key Crank


Models: 2006 - 2007 Chevrolet HHR

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This PI was superseded to combine information from AIC3193 due to both concerns coming from same harness issue. Please discard PIC4125A.


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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
A customer may bring the vehicle in with a Reduce Engine Power message on the DIC. Any of the following codes may set:

P2120: Accelerator Pedal Position (APP) Sensor 1 Circuit

P2122: Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage

P2123: Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage

P2125: Accelerator Pedal Position (APP) Sensor 2 Circuit

P2127: Accelerator Pedal Position (APP) Sensor 2 Circuit Low Voltage

P2128: Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage

P2138: Accelerator Pedal Position (APP) Sensor 1-2 Correlation

In addition, on vehicles with the 2.4L LE5 Engine (VIN Code P) only, the following codes could also occur:

P0651: 5 Volts Reference 2 Circuit

C0561: System Disabled Information Stored

P0326: Knock Sensor (KS) Performance

P2135: Throttle Position (TP) Sensor 1-2 Correlation

P0335: Crankshaft Position (CKP) Sensor Circuit)

It has also been reported that the cooling fans may run constantly due to this condition.

Recommendation/Instructions:
It has been identified that the engine harness may contact the purge solenoid bracket, causing harness damage and exposing the wires.





Inspect the harness and repair any necessary wires and secure the harness away from the bracket to prevent harness from grounding on the bracket.
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Might take a look at this tsb. here is a link that will show a pic. of the area to check. https://www.chevyhhr.net/forums/show...light=PIC4125B post #15

 

I have a 2006 also sounds like mine did the same thing, whenever stopping it felt like it was going to stall and the idle went a little wacky don't think it was as bad as yours, I switched to mid grade gas and it cleared up, I dont think the little car likes the new ethanol blend gas.