P0507 is Idle air Control System RPM Higher than expected. Scan the MAF Sensor, TPS and O2 Sensor

 

Thank you DrLoch What parameters should I be looking for? Sorry for all the questions. Is there a post that might reference them?

 

You should have noticed when the idle was 200 RPM above normal.

 

Thermostat replacement is the same for all HHRs.

https://www.chevyhhr.net/forums/how-...l-p0128-24493/

 

donbrew, I didn't notice due to only owning the car for a month and I'm guessing the codes were there when I bought it because there has been no light on and still isn't on. Those codes were saved codes when I hooked up the scanner last night. I only started noticing the hiccup at highway speeds and started digging around to see if anyone else experienced them. this is my fist turbo car my other car is a duramax 2500, before that it was a cummins 2500. In my opinion its easier to trouble shoot them then it has been with this car so far. But I will get it hopefully without having to visit a GM stealership. Honestly I am on here to see if someone else with this experience can guide a new owner in the right direction.

 

Thank you RJ RS SS 350, that will save me and looks pretty simple.

 

Your welcome, yes very simple.

I haven't seen an issue like you are describing here before. If you would have used the word 'flutter', I would think there is a problem with the bypass valve system. The way you're describing it though, makes me think maybe the brakes are hanging up or something like that. I don't think a clutch problem would cause this...

 

It honestly feels like when you hit a puddle on the highway. It doesn't jerk you around but there is a slight hiccup is all I can think of. You can feel it when it does it which is why I'm surprised it hasn't tripped a light. The sweet spot seems to be at cruising speeds when you manually lift your foot off the accelerator for that quick deceleration. On cruise control your don't feel it only when you are controlling the throttle. It is super strange. I honestly thought it was the plugs because it has that same jerking hiccup that a misfire plug does, so I changed them with OEM plugs. Ran a can of Seafoam through it because I thought something like an injector may have some dirt, that didn't do it so now I'm on here asking for the help from the best of the best when it comes to our cars. At this point I will focus on fixing what is in front of me from the codes stored and go from there I guess.

 

If the CEL is not on stored codes mean nothing. Go ahead and clear them unless you need an emissions within a month or 2.

P0507 is a Type B DTC

 

Don't fall for lower priced thermostats, get the OEM - Thermostat - (2006-2011 All Models)
ACDelco 131-158 GM P/N 12622410