Yea some day it runs great then other days it has lag but stop to stop light it does great no lag. It was colder out when it came on I was on the freeway my temp was only at 178 and from what auto zone said normal runing temp is 180 and it threw P0128 and that also said it could cause power. It mainly has lag on the free way when I try to accelerate and in doin about 60no thanks for all the info

 

Cody26: here is a tip for you on finding your current posts/threads - move your mouse over your name in the upper RIGHT corner - that will pop up a dropdown list, where you can then click on MY POSTS - that will bring up a list of your latest posts.

also, whenever referencing a code down loaded as a result of the Check Engine Light, ALWAYS quote the exact code (ie: p0128) - don't just quote the words or description from the parts guy. We need the code itself, as often the words are wrong (ie: saying sensor, rather than solenoid).

 

Time to replace the thermostat for sure then. Get a genuine ACDelco one, rather than an aftermarket one, as some of the aftermarket ones don't seem to be built to the correct specs.

Here's a how-to on replacing the thermostat - not a difficult job overall: https://www.chevyhhr.net/forums/how-tutorial-library-21/how-save-$350-00-thermostat-replacement-2-4l-p0128-24493/

 

But would it like cause power lag

 

Ok sorry I'm new to this

 

Still don't see how that's going to cause a "performance" issue. Or the lag he's referring to. It's not like the ENG PWR REDUCED. Now that's lag! When I get a MAF CEL (or even pending) boost will not go over 4-5lbs. I'm so used to it that I can feel a "click" in the pedal, grab my scanner, sure enough pending "MAF performance, hi or low" Clear it and back to normal

But if Cody still has 14 lbs boost it doesn't seem like the ECM is limiting performance.

-LOL, takes me so long to compose a reply we're on a whole new page. Sorry for the repeats!

 

Yea it's pulling 14 lbs boost just everyone I talked to said it was the thermosta causing the lag how do I fix the ECM from limiting proformance

 

I'm just confused how the thermostat causes a lag? I've been searching through our forum and the cobalt ss forum. Thermostat yes, but I've seen nothing regarding it causing a lag in performance. You need to fix the stat first, regardless, because you don't want any overheating. Aluminum hates that! As stated, make sure you go with genuine Delco parts and dexcool!

-I'm still hunting around for thermostat causing performance issues. Makes no sense, especially since you're still seeing 14lbs. The ECM isn't limiting performance with that boost pressure. As far as lag, I'm digging around?!?

How many miles on that SS?

 

Ok thanks any advice on what it could be would really help

 

Me, I'd replace the thermostat first (as it does need replacement anyways), then see if the lag issue is gone. I don't see how the two issues would be related either, but who knows the mysteries of the ECM

FYI: the P0128 will disable the A/C and blank out the digital temperature display with "----".