Have a 2006 HHR and has always run nice and strong. The temp dropped here pretty cold (-20ēC) and is headed lower still. I forgot to plug it in and when I went to start it the next morning, she just plain wouldn't start up. Engine turned over just fine and almost caught a couple of times, but just plain wouldn't start. So plugged it in and let it warm up a couple of hours. When I went back out and finally got it to fire up, she was badly misfiring. Didn't have time to work on it so left it plugged in for the remainder of the week with a trickle charger to keep the battery up. Was able to pull it into the in-laws garage to work on today (only -26ēC today). Pulled off the air cleaner and checked the plugs, cylinder 1 & 4 were badly burnt and worn down. Zipped out and grabbed a fresh batch and replaced them all, but engine is still misfiring. Pulled the codes had a B2AAA & P0300 stored. Erased the history and it'll pop P0300 but nothing else.

Any suggestions would be greatly appreciated as I'd rather just not throw parts at it until I luck across something.

 

Could be dirty throttlebody, you say you got new plugs but didn't specify what brand , the HHR's need AC Delco 41-103 iridium plugs. Use a quality throttlebody spray cleaner

 

P0300 means random misfire; I'd guess a fuel supply problem.

 

I agree I would check the fuel pressure.

Run some good fuel system cleaner through it also.

How warm can you get the car in the garage? At those temps makes me wonder about moisture in the fuel.

 

It had Bosch Fusion plugs in it. Unfortunately they are unavailable locally, so had settle for the Bosch Platinum plugs.

The garage is unheated and not sure we could do much of anything to get any heat built up in it at this temperature. It's slated to get colder for the rest of this upcoming week. Will check the fuel pressure and throttle body tomorrow and see if that gives any clues.

Will have to make a few phone calls and see if I can chase down a heated garage. Not sure I actually know anyone who has one. Even tho it's extremely cold in the winters here, just doesn't seem like anyone bothers.

Thanks for the suggestions, was kind of what I had in mind.

 

Bosch is "cheap Chinese" or equivalent.

It used to be a good name like Sylvania.

 

I tried a set of Bosch plugs , took them out after 3,500 miles , misfire codes , the 2.2 didn't like them!

 

the ac is your best bet to run ....my misfire went a way with about 2 bottles of techron clean them injectors

 

Step #1..Order AC Delco 41-103 Iridium plugs.

Step #2..Remove Bosch plugs and throw them in the closest snow bank.

Step #3..Install Delco plugs.

Step #4..Disconnect the NEGATIVE battery cable for thirty minutes to clear any stored codes.

Step #5..Reconnect the NEGATIVE battery cable and drive your HHR normally.

Step #6..Never stray from AC Delco plugs again, the Ecotec engine family was designed around them.

 

That's what I said! In post #2!! Just not the lobotomy part!