I'm not saying a code P0128 would cause Cody's "lag" problem. I was just stating the possible(and most likely) cause for this code. Now after his update about his temps, he probably has a thermostat issue and probably has a P0128 code. Sure wish he would post the actual code numbers.

Dbeluscak. I was just saying you most likely never saw a P0128 because your's was overheating when you had problems.

As far as Cody's lag. Could be any number of things. I would take a closer look at the boost numbers. If it for certain holds that 14lbs, even when "lagging", then I would rule out a boost system leak. Now if you see ANY drop in that boost when it lags, then it may have a leak. Then it would be time for a leakdown test.

 

@Cody
Looking for the history of your SS...mileage? Auto or 5spd? As Doc said, we really need all the info you can provide to help out.

I gotcha FMG. I did pull the stat and tested it. Which led me to the head gasket. Was comparing my ECM lag, which is unmistakable. Sounds like a power transfer issue. But I don't think he mentioned the trans. Could be a clutch!

 

It's a 5 speed manual and it roughly has about 79,000 miles on it and the code was P0128 when auto zone looked it up it pulled up thermostat thay said it is some weird sensor that GM on

 

Lol...no offense to autozone but a thermostat isn't a very weird sensor or sensor at all. I suppose they could've thought the temp sensor. But more likely that your code is stat related.

How about previous owners? At 79k, I doubt it's had the clutch replaced. Mine are all auto (for now!). Previous owners could tell us if it's had a "rough" life. My wife's SS definitely had one, unfortunately... It's been given new life but has spent more time in surgery than out and about!

 

Yea it has had 2 previous owners but I have all the paper work of the maintenance and their isn't nothing serious on just besides the normal maintenance. They also told me that HHR is soppost to run 180F he said that normal running temp

 

Any mention of a clutch replacement? The SS does tend to attract more "spirited" driving. Especially when advertised with No Lift Shift. When you notice your lag, any funny smells? Probably wouldn't pick it up on the highway, but that's how I tell when a clutch is on its way out.

 

So it happens on the freeway when you're at 60 MPH, and you hit the gas to pass someone. Are you in 5th gear? Maybe you need to downshift? If I'm going that slow, I'm often already in 4th gear, and I might even downshift into 3rd to pass, especially if I were on a steep grade. Yes 60 to me is a bit slow

Maybe stoplight to stoplight is good because you're in a more appropriate gear? Not trying to offend, just don't know how much experience you have with a turbocharged manual trans car.

And I think I read that high boost at lower RPM's is bad for the motor. I think it had to do with crankcase pressure?

 

Cody26 - just to clarify for you, in case you haven't read up on the thermostat issues, here is how the P0128 is generated: the coolant temperature is monitored from engine start-up - if it does not warmup fast enough, and reach a certain temperature within specific constraints, the following happens:
- the ECM detects the condition and generates a fault condition
- the fault triggers the P0128 code
- the CEL lights up on the dash
- the A/C is disabled

Typically it is caused by a rubber gasket deteriorating on the movable valve in the thermostat, jamming the thermostat open. When this happens the coolant does not warm up fast enough. Subsequent restarts with an already warm engine may clear the CEL. The CEL can be easily reset by disconnecting the NEGATIVE post on the battery for a minute or two (even less in my experience).

 

Not exactly. The SS 2.0 has a 180 degree thermostat. Operating temp range is generally 183-205 depending on variables. Could run even hotter with high outside ambient temps.
If your temp dips back below 180, it usually points to a thermostat problem.

To me it sounds like you may have 2 seperate problems. Replace the thermostat with an AC Delco one. Off brand thermostats have been known to cause problems before in the HHR's.

 

Ok I will go ahead and replace the thermostat and see if that's helps what was the second problem. I was going to put it in the shop to have it looked over to see if their is something I'm missing is that a good idea