Misfiring. Need Help.

[cfrierson11]

I had my codes read and I was misfiring on two separate cylinders. I finally replaced all the ignition coils and the shop called and said it was still missing. In recent months, he gas mileage has become atrocious. Down to around 14 mpg according to my SID. Can anyone help, please?

Another issue I am having it every now & then, my SID notifies me that my engine oil pressure is low and that I need to shut off the engine. It will only come up for seconds at a time and go away. The car seems to be running fine aside from the misfires. Any thoughts? Bad sensor? Or something much worse?

Thanks in advance.

-Cody-

[ile2010]

Could be many things, some which are above my pay grade. When you replaced the coils, did you also replace the plugs? If so, which plugs did you use? I'm new to the 9-3 (just got my '08 Aero SC days ago), but on my 9-5, I know to use only the NGK laser platinum ones, and from what I've read on the 9-3 so far, this seems to be the case as well (albeit a different NGK LP plug).

Next I'd check the wiring for the coils for excessive wear. Could also be an injector issue, but someone else would have to advise on how to check for this.

[cfrierson11]

Thanks for the reply. I changed the spark plugs around this time 2014. I can't remember the specific brand, but I do know I tried to go cheaper than the NGK. Which now I'm realizing may have been a huge mistake. I did not put new plugs in with these coils I just had installed. Thanks for the advice. Hopefully I can narrow it down and get it right again soon.

[ile2010]

You're welcome. In misfire situations, I tend to go from cheaper solutions to more expensive. With my 9-5, I first replaced the plugs. Code came back. Replaced the ignition cassette, code went away. The plugs themselves didn't look too fouled when I removed them, but the car was new to me and I didn't know when they were last replaced. I say go for the NGKs and see if that does the trick.

[cfrierson11]

That's my plan. I misread the website and thought the ngk's were $100 a piece, when in fact that is the price for all 6. If I would have known that, I would have done it right the first time. So I'll be purchasing and installing them in the next week.