I also have a 2003 2.2L ecotec manual transmission.I have changed plugs,coil,map sincer,still have a misfire problem,i think somthing is wet inside but what that might be i don't know.Any suggestions

I worked on another fuel injected vehicle and found that it had an injector problem which had caused the check engine light to com on telling me that I had a random misfire.I did the same as you did and changed the knock sensor ,the crank position sensor and the cam position sensor only to find out that is was a distributor and injector problem.I would recommend that you test your cam and crank sensor and make sure that they are working properly And if the sensors are good then I would check my fuel system including the injectors to make sure there are no bad ones.

I have a 2005 Chevy Cavalier. I had a misfire problem, and I changed the coil pack, ignition module, plugs and also changed a purge solenoid. Car ran great for 3 days, then misfired again. I saw other peopple had similar problems so I just took it to the dealer...they changed the spark plugs, coil pack aand ignition module. Told me my parts were bad. You have to use the OEM spark plugs...if you don't, then they will blow your ignition module and then possibly your coil pack. Cost me $650 bucks to repair. But it's been running fine ever since. I got a refund from Autozone, but just make sure you use the OEM spark plugs.