Golf 4 1.6 sr estate, lack of power, number 4 cilinder spark plug always wet, as soon as you load the family and try going up a hill it takes you a while

To find out, check the engine number with the VIN plate.
Take it to a garage if you don't know where the plugs are.

Chicken and egg - which came first? If the spark plug stops sparking it will soon become wet with fuel but if there is a fault such as a dribbling fuel injector (assuming it is an injected model rather than a carb) the spark plug will soon become wetted with fuel and consequently stop sparking. The fact the other spark plugs are sooty does indicate an excess of fuel but only systematic checking will find the fault.

What make and model of vehicle ?How many miles on it ? When does it lack power, all driving conditions or just under a load, such as going up a hill under heavy throttle ? A couple of thing's right off that it could be is a plugged catalytic converter , plugged fuel filter or a weak fuel pump. Are there any lights lite on the dash , check engine light etc.. Have you experienced any strange noises or happenings ,like engine back firing. How does the engine run ,smooth ,ruff ? Have you had spark plugs changed and wires if it has them ?

check all your filters, air and fuel

First change your fuel filter. Get good patinum spark plugs and new wires. A cold air intake would help as well.

It sounds like it is loosing spark somewhere on the ignition circuit. e.g HT leads, distributor cap, one or more spark plugs faulty. The above usually happens when the engine is taking more load than usual, like going up a hill and the r.p.m at about 1500 - 3000.Try it again in a lower gear 1st or 2nd with the motor r.p.m high, about 5000 revolutions per minute.

Regards
Phillip

you have 4 clips holding the cover down.you have to disengage clips to move cover.

check coil or powerpak

Do you know how check if every cilinder is working? with the engine in idle, go to the distribuitor cap and carefully unplug one at the time, every cilinder spark plug wire,in the cilinder you dont see a diference in rpm variation, that cilinder is not working, replace spark plug, if you see spark jumping fron the distribuitor cap torch the spark plug wire, another cause to a cilinder fail could be a loss of compression in one or more cilinder

You should try doing a tune up change spark plugs, wires, pcv,and fuel filter.it's reasonable to assume that the rings and
valves (inside the engine) have become worn. Worn rings
and valves will cause the engine to have low compression
and low compression = weak power.
You may be curious as to why the engine's lack of power is
most evident when driving up a hill. Well, when a vehicle is
going up a hill, the engine is under more stress than when
driving on a flat road. Therefore, any wear in the rings/valves
will tend to be revealed - in the form of compression - when
the engine is under stress.

you will need to have a mechanic verify that the rings and/or
valves are indeed worn. Incidentally, this generally involves
what's known as a "wet compression test".
If the mechanic tells you he positively confirmed a worn ring
and/or worn valve condition, don't immediately authorize him
to do the work. Why? Because, this type of work is very
expensive and therefore you'll want to get several opinions
before jumping into anything. By the way, even though this
vehicle's high mileage strongly points to the above diagnosis,
it's possible the cause of this problem is something else.
For example, one of the electronic sensors that controls the
engine may have gone bad. hope this help have a nice day.