I have a 2009 HHR, 2.0 liter, automatic with about 45,000 miles. About 3 weeks ago the OBD (Check Engine) light came on. I read the manual and it said one of the reasons might be the fuel. There are only a few places I buy gas and have had no problems. I filled the vehicle up and the light went out the next day. It came back on a few days ago. I have scheduled to take it into the shop next week. I filled it back up and the light off for a while then came back on. Now the thing is getting terrible gas mileage. I took the fuel cap off and put it back on on several times. Could it possible be something that I can check out and fix before spending a fortune on it at the dealer. No, I did not buy the extended warranty. Any suggestions.

 

Without knowing the actual code, I really wouldn't know what to suggest.

 

First step.... get to an autoparts store that does free scans and get the codes. If they offer to "clear the codes" hold off on that at the moment..... just get the codes and post them here.

 

I went to Autozone and had them put their little Code reader on my HHR. It came back P0301 -- Cylinder 1 misfire. It listed about half a dozen things. The person at Autozone said sparkplugs (which is one of the possible causes). The vehicle has about 46000 miles on it. I thought the plugs were supposed to be good for 100,000. Other possible causes were vacuum leak, fuel pressure too low or too high. I checked the fuel economy this afternoon and it's gee\tting about 22 mpg.

 

Check this thread..... might be some clues. https://www.chevyhhr.net/forums/problems-service-repairs-42/cel-fuel-injector-18749/


I wouldn't think spark plug but that's an easy check..... swap 1 and 2 and see if the problem moves. But I'm leaning to a plugged injector, or even just bad gas.

 

Unfortunately, the 2.0 SS has an "oversensitivity" in the algorithms that throw the misfire codes. I've run into that a lot. Poor and rushed programming on GM's part.

The good news is..... You should still be under warranty. Let the dealer worry about it.

 

Vacuum leak = gas cap loose, give it a 100 miles to reset itself.

 

I filled it up on Monday, drove it about 95 miles. Filled it back up on Thursday and checked the fuel economy. Getting about 22 mpg. Not happy with that when I used to get 27-29. Puzzling thing though, after each fill up, usually in the late afternoon, the next morning the light will go off. After driving it some then it comes back on. The P0301 code list also suggests injector(s) and maybe ignition pack. Don't know whether mine has the latter, but, does anyone know if these are covered by the 5 year/100000 mile Powertrain warranty? It is no longer under the 3 year/36000 mile warranty and I did not purchase the Extended warranty. Thanks.

 

How this can be possible?

 

I don't get the logic there either but I know a loose gas cap isn't going to throw a P030X code......