I have this 98 Honda Passport, notice that theres' oil coming from the three spark plug cable unit. this is on the left bank looking in front of the car. the right bank no oil coming out from the valve cover..just on the left bank.. What is the cause of this problem.. Car running smooth and have power..Please advice..thanks

This is the diagram for the 4.6 1998 Ford Expedition.( Notice the numbers 1-2-3-4 spark plugs are on the left side if you are facing the front of the vehicle.) Please rate my answer if you were helped.
Thanks

These Isuzu-built vehicles had many problems with fuel system components. Particularly the sending unit in the tank. Note: If the unit is replaced, the PCM must be updated to accept the new pump calibration before it will work.

often times a set of eyes and hands on a car is better than all the oracles in the world. take it to a muffler or oil change shop, have them put it up on a lift, actually look at it, and they will know immediately where the oil is coming from. you could luck out and find it is a cross threaded oil filter
or drain plug and be happily on your way for less than 10 bucks..

1. Spark plugs removal

1.1. Front cylinder bank spark plugs removal:
1.1.1. Disconnect the battery from car terminals.
1.1.2. Remove the engine plastic cover.
1.1.3. Disconnect the ignition coils electrical supply cable and all three coils connectors.
1.1.4. Remove all three ignition coils screws.
1.1.5. Remove all three ignition coils out from cylinder head.
1.1.6. Remove all three spark plugs out from cylinder head (straight forward).

1.2. Back cylinder head bank spark plugs removal:
1.2.1. Remove the inlet manifold out from cylinder head.
1.2.2. Disconnect all three ignition coils connectors.
1.2.3. Remove all three ignition coils screws.
1.2.4. Remove all three ignition coils out from cylinder head.
1.2.5. Remove all three spark plugs out from cylinder head (straight forward).

2. Spark plugs installation

2.1. Refit all in reverse order.
2.2. Spark plugs tightening torque = 2,8 +/- 0,3 daN.m
2.3. Ignition coils tightening torque = 0,8 +/- 0,2 daN.m

not good, head gasket or a cracked block

20/50 cheapest you can get and change every 6000miles ,with a oil filter every third oil change

it is actually called the oil sending unit. It is located on the lower left side of the engine near the oil filter.

the plug for oil pan maybe loose or new oil filter is
loose . if you can i would go back at that shop
and tell them

use brake fluid to refill it.

head gaskets do not "dry out"
running rough indicates injector problems --stale fuel dirty injectors or sticking injectors
run the fault codes to determine fault area
oil around spark plugs indicates that the rocker cover seal under the plug tube is leaking into the plug area