If it is wet from water, I would suspect the drain for the condensation water is plugged with crud disturbed while changing the cabin filter. If it is wet from engine coolant, I would suspect a leaky heater core.
The service will vary from car to car depending on the condition of the vehicle. Some typical services done at this point would be changing transmission fluid and filter, replacing or adjusting the timing belt and replacing the spark plugs.
If you replaced the oil filter, it takes 3.9 quarts. If you didn't replace the oil filter, it takes 3.7 quarts. As a mechanic, I would never recommend changing the oil without replacing the filter also. Toyota says you should use 5W-30.
Could be as simple as a very dirty fuel filter. I would start with replacing the fuel filter.
5 quarts would be average.
I would try replacing the fuel filter first.
First step try changing the fluid and filter First step try changing the fluid and filter Check
Depends on what vehicle it is installed on. If the filter is mounted in the tank then you would not replace the filter unless the pump needed replacing also. If the filter is outside the tank it can be purchased separately.
i would defiantly start by changing the fuel filter
Probably replacing the typical enriched wheat flour of pastas and breads with whole grain versions. Also, reducing saturated fat by replacing creams and cheese spreads with lower-saturated fat versions (such as tomato sauce) would be a good step.
Assuming this is the 4.3 engine, minor tune up consists of replacing the spark plugs, air filter and fuel filter. A major tune up would consist of replacing the spark plugs, spark plug wires, distributor cap, rotor, air filter, fuel filter and pcv valve.
The filter may be lose if this is not the case the threads around the filter may be "stripped". Try changing the filter if this does not work I would take your vehichle to a certified mechanic.