Truck has been running real rough for the past few weeks and been sucking the gas like you guys wouldn't believe. A 35 gal tank is getting me 400km to a tank. Ouch.. Anyways, so I put a code reader on it and I forget the code but it said Misfire On Cylinder 2. I checked #2 cylinder and the plug was bone dry which is good so I checked cylinder #4 and the plug is soaked. Why my code reader told me its cylinder 2 is beyond me but I've got new plugs and new wires that are 6 months old. I swapped the cylinder 2 and 4 plugs and its not the plug. I've noticed that it happens when I go through a mud hole but then goes away 5 min later, which is understandable because I do offroad the truck. Now its constant for the most part. I get the odd start up where its not misfiring. Where should I start looking?

 

Plug wires, and distributor cap first. Getting wet, and missing is usually a sign of leaky wires.

What's compression like?

 

Mine has similar problem. Any rain or moisture and the thing takes forever to start sometimes and runs like shi1. Carwahes kill it instantly.

 

Compression is 139

 

Well, I can say I had similar symptoms in my 98 360 and it turned out to be a bad temp sensor. With a low /no temp reading to the PCM it was having intermittent rough run after start up, run ragged first 5 miles, clear up and run good. It came down to the low temp reading having the PCM give it some extra fuel (8 mpg's). I also had a crack in the distributor cap. K.

 

Good advice above from HeyYou, and also don't forget the old TSB about routing the wires...anytime you are fiddling around with them...it really does make a difference!
Here's a link to the 1998 TSB:
http://dodgeram.info/tsb/1998/18-48-98/18-48-98-v8.htm