Van overheated ... I replaced the cap and rotor button spark plugs and wires. And its still idle rough ... I used a odii scanner and it said muliple misfire .. So i took it to the shop and they said a misfire on 4-6 , the cap might be bad because i use a spider cap and they go bad .. So i replaced it and its still idle rough .... Dont overheat no more but i notice the oil pressure gauge keep dropping after the van heat up ... Help !!!!!!!!!!!!