About a day after my O/R install my check engine light came on. Car doesnt act any different than it did from the end of install until the light came on. How common are defunct MILs?? I dont think it could be anything else. The exhaust is on tight and i put new gaskets on and everything.
best thing to do is have the code pulled and make sure it's the mils not working correctly...
As for how common, depends lots of people had issues with the plug and plays, although most of those were after driving for awhile.
I had two sets on my car, plug and play and the splice in ones, both didn't work. I was told to use spark plug anti fowlers to move the O2 sensor out of the exhaust stream and it worked great, no light anymore.
Buy the anti fowlers and it will solve your problems as long as that is your problem, Check your codes, I changed my mil eliminators from side to side to verify which mil was bad and then I checked to see if the codes were the bank 1, bank 2, downstream or upstream.
Yeah definately get the code pulled. You could have a leak somewhere which may trigger the fronts to throw a code.
What kind of mil eliminators are you using? Some you have to break the little tab off or they won't plug in fully. Others, if you wire anything backwards, it'll throw a code. My guess is you have a loose wire.