purchased a 2000 jeep wrangler

I recently purchased a 2000 Jeep Wrangler from Grand Motor Sales, After driving for less then 3 months it started setting a code p303 which should have been an easy fix,but someone put radiator seal into the engine causing the cyl 3 coolant ports to plug solid. This also caused a coolant leak into chamber 3 which set the code for misfire. I would not recomend anyone purchase anything from the used car dealer. I was told by the sales person/owner that this vehical was his brothers. The only reason anyone would add radiator seal to a vehicle is to hid a problem!