But you must use oem when dealing with the 02 sensors.
Huh? Thats a new one on me?
I totally agree, and the Commander is NOT the only vehicle that experiences this, that there a lot people complaining about problems after switching brand or type of plugs different than OEM, even though they are suppose to be equilvalent and perfectly compatible replacements.
I have always "assumed" it was because of new ignition systems and ignition schemes the manufacturers have been using on their engines were the cause, i.e. new kinds of ignition systems or schemes are much more sensitive to the subtle differences between brands or types of plugs.
I can't imagine how O2 sensors are behind problems with different than OEM plugs? But I'm open minded, and definitely want to hear the explanation to consider if its true/plausible or NOT? I'd agree that incomplete ignition would wreak havoc with the O2 sensors, that doesn't make the reverse true that just because O2 sensors are there they create some sort of problem with ignition because of subtle differences in the plugs.
I have a partial explantion that would explain some problems, BUT NOT ALL. The wasted spark ignition scheme, which some Commanders have and lots of other vehicles as well. This scheme has 2 spark plugs share 1 coil, the plugs are in cylinders 180° out of phase, and both plugs fire at the same time, by the one ignition coil. For one cylinder, its when the spark is needed and the other cylinder is when its in the exhaust stroke, where the spark won't hurt (it can even help burn any unburnt fuel being exhuasted which improves emissions). This means the plugs fire twice as often as the old systems, so you should replace them twice as often. But the big thing to realize is how the coil fires both plugs, the plugs are actually wired in series with the coil and the ground. The coil actual pulls up current from one plug as drives down current to the other plug. What that means is current flows the opposite direction in half the plugs in the motor. That is no big deal, until you try to use platinum or irridium plugs, those plugs have harder metals that resist the errosion of the metal from the spark (the whole anode and cathode deal). But, if you reverse the current in one of those plugs, the spark now jumps from the softer steel to the harder platinum or irridium, and that causes the softer steel to errode even faster than if it was steel to steel. This is why they now have double platinum/irridium plugs, with the same metal on each electrode on the plug, so the plug can handle current flowing in either direction and last equally as long. BUT, that still shouldn't create a problem with ignition right away, and people complain about that, as soon as they switch brand or type of plugs, that should work equally well, they immediately start having ignition problems. All that I just described, means half the plugs would wear down/errode much faster than the others, you'd have problems 5k miles down the road, NOT right away.
So, I really haven't heard a good explanation why lots of modern engines have ignition problems immediately, when they switch brand or type of plug that should be equally compatible?