How many miles before i change spark plugs on a 2006 mercury marinier

ok is this the first time that you have changed them, most plugs will go for 60,000 miles but you be the judge, if you get bad milage than change them

If you are saying it takes a long time to start the engine, have you checked fuel pressure before and after cranking ?

Spark Plugs ---every 3 years on all vehicles, regardless of miles
---- and not over 50,000 miles

Need to ask a specific question,such as something your having
touble with

If you haven't even looked at the vehicle !

The plugs are under the COP Ignition Coils

They get changed every 3 years or not over
60,000 miles of use & use OEM type plugs

Any brand that is the correct center electrode
size,not all brands are the correct shape

Front O2 Sensors get replaced at 100,000 miles

Modern spark ;ugs can easily go 50,000 miles. If you think you need new plugs, go ahead and change them out. It certainly wouldn't hurt, and it might give your horsepower and fuel mileage a little boost. I would recommend using Iridium spark plugs from either NGK or Autolite. Personally, I use E3 spark plugs. They did wonders for my old '96 4.3 GM V--6. I would also invest in a premium set of spark plug wires, Don't scrimp on the wires, they are a vital link in the ignition system. A cheap set of plug wires can cause multiple misfires which would play havoc with the on board computer.

the most important (in my opinion) is changing the transmission fluid( transmissions for those cost about $4,000.00 to replace) its supposed to be changed every 30,000 miles. ( spark plugs can last up to 100,000 miles before needing replaced.)

Yes, the timing belt, spark plugs and spark plug wires, fuel filter, O2 sensor/s, a transmission service too.

Spark plugs should be changed at about every 25,ooo mile to be on the safe side and it keeps your engine efficient.I hope this helps. Don't forget to rate my answer, thanks.

change fuel filter and drive belt and spark plug wires if it does not have coil packs

I usually change the spark plugs on all vehicles every 10,000 miles.