Should be good, just the injectors show different part numbers, plausible they don’t play well with the other.

 

So you removed the #2 injector from the HHR engine and installed it in the Cobalt engine, right? Perhaps it needs a new seal? Might have damaged it during the removal or installation?

 

Injectors all got new seals, I used the original cobolt injectors, I replaced the #2 injector with a new one for the hhr le8 engine after getting the codes and issues.

 

Check the #2 injector wires.
double check the coil in #2 and the wire harness

https://www.obd-codes.com/p0302

 

Do I have this right? Cobalt engine, Cobalt Injectors, HHR programmed ECM.
I don't know if the crankshaft ring is the same or the cam shafts. I do know that the injectors are programmed/controlled in the ECM.

 

So, then the cobalt injectors should produce the code, but this code is for the hhr injector cylinder. So, I’m thinking move to the coils

 

You now have two different injectors in the motor.

This is exactly the concern expressed in post #18. As confirmed by Oldblue, Cobalt injectors are not correct for the HHR. Whether one of the Cobalt injectors was bad is not important for now. I think you need to install the old HHR injectors. Or three new ones, in 1,3, and 4. Just get 4 HHR injectors installed. The ECM thinks it’s controlling HHR injectors. Am I missing something?

 

Another member mentioned her misfire was addressed with new spark plug boots


From the coil pack

 

What was the outcome of your injector issue, with the cobalt engine in the HHR?
For I have the same exact issue: 2009 HHR and Flex Fuel ECM with a 2009 Cobalt engine non-Flex fuel injectors. I have the old HHR injectors in the garage and I plan on swapping them out this weekend in hopes of correcting my problems. I am getting p0171 and p0172 and some misfires as well.
This is has got to be the issue, I was just hoping to see confirmation in this thread...

 

Why did you use a mismatched engine? Did somebody advise that was a good idea? Did you use the old sensors with the new engine? Is it even the same size 2.2L/2.4L; I think the Cobalt only had 2.2L
They are not even the same engine, the Cobalt had a LAP 2.2L the HHR had a LE8 2.2L or LE9 2.4L
It is the ECM that adjusts the injectors based on data from the sensors. The part numbers are usually printed on the injectors.