Imola20ae

Greeting to all.

I am having a problem with my 01 GC limited, it has the 4.7L w/ quadra-trac I have just shy of 60K on the odo, and its my wifes so it really doesn't get driven hard. Today I did some typical 60k mile maint. Spark plugs, air filter and transfer case fluid. I had everything done and started her up. Right away I noticed it wasn't running right. I backed it out of the garage and it stalled when I shifted from reverse to drive. Then when I accelled it hesitated somethging terrible. I thought something is misfiring, no biggie. Maybe a coil wasn't secured or something. I checked all the rechecked all the gaps (.040), then made sure that all of the coils packs were seated. I pulled out for another test and it still does it. I drive to Advance and hooked up the OBDII reader and it said cylinder 03 was misfiring. While i was ther I bought a new coil, thinkning that was it, adn returned home to install it. I replaced coil pack no 03 and it still did it. I put the original plugs back in to see if maybe it was the new plugs. Sure enough, it didn't do it with the old plug. I then exchanged the faulty plug and got a new one. Now cyclinder no 03 has a new coil pack and plug. At idle it runs and sounds fine. It doesn't seem like its missing. But once I get up to speed and maintain sy 50mph it rubs real rough. I haven't had a chance to go back to advance to see if the CEL is from the 03 cylinder or from the gas gap issue (ongoing/unrelated).

When I replace the transfer case fluid I did exactly how I've done in the past/how the manual says as well. Fill to the fill hole.

Could it be the transfer case? WTF? Has anyone had any trouble like this after changing plugs or transfer case fluid? I am no mechanic but know my way around a vehicle. It doesn't add up.

Any help is well appreciated, sorry for the long post. Thanks in advance.