I have a 2011 hhr lt 2.2lt that sat for a yr and 1/2 that was running to rich and would run right when we would reset the trim codes. I always used e87 never used e85. Just switched to e85 and tbat helped with the running rich code so now that’s gone and was running fine for like a few days but now it has a constant misfire on cylinder 2 and bank 1 sensor to lean code and was jerking while and running rough while in idle. So I changed and gapped the spark plugs to specifications cleared codes, still same codes came back. So I moved to the coil pack from cylinder one to cylinder 2 rest codes drove it few min later sams codes came back. I proceeded to then check The fuel injectors and swap cylinder two fuel injector with cylinder one reset the codes drove it for a few minutes and it misfired again same codes popped up misfire on cylinder two and Bank one to lean. so I moved onto a compression test and I had even compression across-the-board. I change the O2 sensor upstream right before it sat, but I’m assuming that why it was running Rich it most likely burned up the O2 sensor not the maf sensor, but did add a new map sensor, which changed nothing would like to note that fuel injectors had lots of carbon buildup around the O-rings to the point where I had to pull them out one by one and some boots even stayed in and had to be out with plyers. I did not change the fuel injectors, just simply swapped them from the bad cylinder, and as stated did not get a misfire on the cylinder that now has cylinder 2 injector. Have not done a few pressure test, but will be doing one when we change the O2 sensor and while my mechanic is changing the O2 sensor, I will be adding a new fuel injector to cylinder two to see if it improves the misfire. Anyone have any suggestions on what to check if none of the things listed above, solve the misfire. Would like to note that the misfire is consistently only on cylinder number two.

 

Change all 4 injectors, insulator cups and orings. Clean out the fuel rail also

 

Ik you recommend changing all fuel injectors would it be possible to just change the one if it takes care of the misifire and then I can go back and change all fuel injectors super easy on this car to access. So I don’t mind double working. Will also be checking the wire harness to see if it’s even getting power probably first I should have done was check the connection to the injector and the coil pack!

 

Okie dokie. Change the fuel injector

 

What is E87? 87 octane with extra ethanol?

What diagnostic trouble codes are you getting exactly?

How does the car behave qhen you cold start it?

 

Pending codes were p0171 and p0302. Stored codes were catalysis system insufficient, the two I listed before and an Evap leak I believe would have to double check but the two most consistent codes are the bank one to lean and cylinder to misfire. Soo 87 is just reg gas. Never had a oroblem
ut when it was running to Rich I switched over to recommended fuel which was e85 and it stopped running rich. The car is a flex fuel, Ik I replaced the fuel pump but idk if the pump was e85 compatible.

 

Read this thread. Lots to get thru but I’ve written about this kind of problem a few times and ima not gonna do it today. Questions welcome.

https://www.chevyhhr.net/forums/prob...or-code-65196/