92-wet road fun-now tach gone

recently bought used 92 lesabre
had code 41-cam sensor replaced got rid of service engine light
did plugs & wires, is that di-electric tune up grease supossed to be used on the actual connections or just around the boots to keep dirt & water out...anyway...
took the car on holidays.600kms was fine..drove next day 100+ and roads became very wet-puddles etc. going up hill car shudders and had power loss. I stopped checked around & under then kept driving..did the shudder thing a few times more, when roads were dryer it did again but less violent
only did this uphills..
also water getting into back seat floor(half inch deep on passenger side)
took all wheels off and checked for bad steering component then replaced fuel filter..was fine all the way home despite some mild rain...
with the water in backseat thinking I have hole in gas tank also
but next morning my tachometer doesnt work, now I.m thinking bad coil pack or wiring harness to the coil packs, The cam sensor wires also lead to the coil pack, water in the connection could cause shudders & power loss,the engine does have slight miss at idle,
only 121,000km so I.m thinking its not the timing chain..but
any similar experiance or Ideas helpful

OK the tachometer came back on after a couple of Km's, I hope this isn't going the way of my old 87 Chrysler LeBaron, that would mysteriously stall every day for a week and then be fine for 6 months etc, etc.