help with misfire on Cylinder #4
 

I've been reading the posts about the misfires on cylinder#4. The one I have is intermittent, it comes and goes. BY that I mean the check engine light will come on then turn itself off. The only code stored is the misfire on cylinder #4.

I know others have stated that it might be from low compression...but this one being random, does not seem like it would be a compression issue.

There are not noticeable signs or symptoms. The spark plug has been replaced and the coil packs swapped. I guess the only thing left if the fuel injector.

I have the same issue in the cylider #2 with the code P302. If I remember well, there´s a recall in due to the fuel return line, that re-circulate dirty gas... probably that might be...

does anyone have a number or the details of the TSB?

I had a #2 misfire on my 2007 HHR. Replaced plugs and swapped 2 to 1 coil pack. Engine light flickers, stays on sometimes, then goes out. This is intermittent throughout the month. Instead of throwing a bunch of parts at this problem, I decided to have the dealer mechanics do some diagnostic work. Turns out this intermittent misfire has been caused by a worn valve guide and burnt valve! Bad compression leads to nasty light off. They replaced the cylinder head today under the 100,000 mile warranty. My HHR had 63,000 miles on it when this started. Same thing happened to my friends HHr at 48,000 miles. Seems the valve would seat every so often, but was slowly wearing out. I believe they have some bad machined heads out there unfortunately. Just something to think about.

Curly
Same problem with my 2008 HHR, I just purchased Jan 2011. They replaced the cyclinder head today. Did this correct your issues and is running okay now?

Misfire cylinder 1 on 2010 hhr and service Traction and Esc light along with engine light, does anyone know why this would happen.

What is the code that was downloaded? The actual code, not a description.

What motor? 2.2/2.4 or 2.0? And how frequent has it happened?

The Traction and ESC and engine light come on because of the misfire.
You would need to diagnose the cause of the misfire. I don't know from here.

Hello rodfat,

We're sorry for the misfire you've experienced on cylinder 1 in your 2010 HHR. It's good to see the mods provide their insight. Have you considered getting this checked out by the dealer? We'd be happy to assist with the process and look into this further for you. Please feel free to send us a PM if interested.

Sincerely,

Eddie A.
Chevrolet Customer Care

2009 HHR Misfire cylinder 4
 

I am having the same problem. Have replaced plugs and wires. Light came on again, the car was checked, plug, wire and injectors. Could not find anything. My next step is to see the chevy dealer. My car has over 107,000. This is the first real problem I have had with it other than the rotors. Apparently need to use premium or factory rotors when replacing original equipment.