1) Check BOOT + BONNET FLOOD
http://www.automotiveforums.com/vbul...d.php?t=893556
2) Check spark plug seal
http://www.automotiveforums.com/vbul...d.php?t=893206
3) Check COP (coil) Test
http://www.automotiveforums.com/vbul...d.php?t=906504
4) Fuel Injector check
http://www.automotiveforums.com/vbul...d.php?t=906693
The oil seals for spark plug boss tubes will leak oil ,THE BONNET will leak water and cause a short, thus causing misfiring, or shorted coils.
The misfires on cylinder 3 of a V6, and cylinder 4 of a V8 (L-banks)is usually caused by water rolling into the spark plug boss of those cylinders, the water will roll along the ignition buss line and into the COP cover in the rear.