Hi all, new guy on this site, new guy (old dude), have '06 H3 and the check engine light came on about 8 months ago. Was told it was a dirty injector, put some "cleaner" through and 2 days later the light went out. Then about 3 months after it came back on, tried the cleaner route, it went out. about a month went by and it came on again. So I ran into a buddy who has an 08 H3 and he told me about the possiblility of the plugs may need changing. So to get to the point I just recently changed all 5 plugs, but the light came back, but I noted that the #1 plug and coil were bad looking, so I changed out the coil also, I was reading your forum on all this and now I am trying to figure out what is going on. I have on 55,000 klm (33K miles) on it and don't know what else to do any suggestions would be great. Sorry for the long winded post.

 

Welcome to the forum. Long winded is ok, you were thourghly descriptive, and that helps. Do you know the actual code itself?

 

Hey thanks for getting back so quick!!
Yes its the same code I got all the times before, P0300 which onstar reports in a intermittent missfire. So I am going out later tonight to the local auto parts store and try the SeaFoam additive.
If that dosent work, then...........

 

Did you do the sea foam yet? If that doesn't do the trick a last resort would be to clean the MAF sensor and while your at it the throttle body. When they get fouled up it really seems the wreak havoc with the PCM and idle of the 3.5 motors...

If that fails you may want to look into the possibility of a bad cylinder head, it is a known issue and even though your out of the GM warranty period if you call the customer service line and play your cards right you might get them to foot a good chunk of the bill...

 

Hey great to have some ideas to follow through with, yes I have bought the sea foam, but having problem understanding how it is put in to the engine.I was thinking you pour it into the gas tank, but it seems that it is put in through the air box. Not sure how to do that, and if you have any advice that would sure help
I am going to try it tomorrow nite after I get off work.

Thanks again for all your help so far.

 

Update
ad to work long hrs this past week, so getting around to working on the rig did'nt happen til yesturday. Took the MAF out and cleaned in and then put in the can of SeaFoam in to the tank. After about 10 miles(16Kms) the light went out andso far has not come back on. Going to take a can of the 'foam with us on this trip in 3 days. If all goes well I will let you'all know.
Thanks for all the help.