Hello! I have a couple of questions and I'm hoping someone can give me some assistance. I have a 2002 Hyundai Santa Fe (v6). My CEL came on and so I took it to AutoZone to have the code read. It came back with P0302 and he said it was most likely spark plugs that needed to be replaced.
I took it to a mechanic and asked them to do a tune-up including the spark plugs. It looks like all they did was replace the spark plugs and do a fuel injector flush, and $600 later, the CEL is still on and now the car is runnning really rough. They told me it would cost another $100 do run the diagnostic tests to see if they could figure out what might be causing the CEL, and didn't say anything about the car running rough. They did say it might be a couple of days for whatever they did for the fuel system to "get out of its system" and that might be causing the CEL now.
Is there anyway that I can narrow down what the issue is? I don't have a lot of money to spend and so I don't want to blindly let them do everything, since I've already spent my car repair budget and not only is it no better, it's actually worse. I'm not sure what other info I can provide, but please let me know. Thanks!