Originally Posted by
big john
Is it actually misfiring? All the time or only under a load? Does it idle smooth or does it idle with a miss?
If it's a P0202 it's probably not a coil or spark plug. Take the connector off the injector and see if it's corroded. Before you do that, wiggle it around while idling and see if it starts/stops misfiring.
You could check the resistance of the injector and compare it to the others. You could also switch the injector with another cylinder and see if the misfire follows the injector.
If it's misfiring all the time you could check the circuit with a test light, should be blinking at a idle. If it's intermittent it could be the injector, the wiring, or the computer.
Definitely a misfire, rough idle but doesn't die. The thing that makes it especially fun is that it only misfires on cold start. If the engine warms up and it's driven a little bit then left to sit everything is happy and no DTC codes thrown.
P0202 is an injector circuit fault, so chasing that by installing a coil won't help that fault. Of course, that's on the back bank, middle, so likely the most difficult of all to get to. For the layman, a wiggle test on the connector itself, if it's possible to get to. A tech worth anything would use an oscilloscope and a current probe, pull the injector fuse, install a fused jumper, and get a pattern.
Thanks, I grabbed a coil just in case but I'll be more than happy to return it. I've got to do this in my driveway tonight so my wife can get to work the rest of the week, so hopefully a new injector fixes it. I'll clean all contacts on the injectors and take a look at the harness assembly since I've got to take the whole damn thing apart anyways. Why does it always have to be the hardest one to get to?