i m going to get a set of bosch +4 spark plug for replacement, what do you think ?

Do i need to buy a new intake manifold gasket when i replace a spark plug ?

 

I would use just plain Bosch Platinums. The 4s are over rated.

 

why over rated ??

 

Do the 02 sports require you to remove the intake manifold to replace all the plugs like the 95 Montero SR's w/ the 3.5L dohc engines? If so, regular bosch plats are not going to be the best. Go for the NGK Iridium's or better (longevity wise). Otherwise you'll be doing extra $700+ spark plug replacements because you didn't want to spend an extra $100 for the longer lasting plugs.

 

Well, in ordinary plugs it is no doubt to buy NGK, but +4 seems to have longest life; that is the reason why I mention +4 earlier. I understand +4 is costly compare to others but it is worth to pay about 3 dollars more on each plug rather than change it often.

So my question is +4 can be able to use in 01 Montero 3.5L ? When I install intake menifold back; Do i have to use a new gasket ?

 

You need a new intake plenum gasket when you reinstall the plenum. Most parts stores have them in stock. About $6.

Bosch +4 plugs do not last longer than NGK's and they are definately not better. The BEST long life plug technology is Iridium. The next best it Platinum. The mult electrode plugs are crop.

A good source for NGK plugs.

www.sparkplugs.com

 

Yes you'll need to remove the upper intake manifold in order to access the spark plugs. If you chose, you can reuse the manifold gasket since it's a metal gasket (though i won't recommend it).


Joel, CA

 

I am no expert by any means, however here is what I would recommend for spark plugs. Reading the factory manual, oem spark plugs for Montero LTD recommended interval is 60K. Also wires are recommended at 60K or 60 months. No need to replace these any sooner as they work very well, obviously unless there is a confirmed failure of one or the other. Labor to replace these will be very high due to amount of work involved to get to them. OEM plugs are most likely Denso, are iridium tipped, of propper temp rating. They are high quality, designed with 60k interval in mind. I would personaly stick with oem plugs and wires. I have an '01 LTD with 43k, still oem plugs and wires. I did pass 60 month interval for wires, but due to cost involved will wait for 60k and replace both. I don't have enough skill and knowledge to do it myself, but am lucky to have a shop that has very experienced Mitsu tech that works on my car.
There is a lot more to propper choice of spark plugs. It would be very long to elaborate here. A lot of it is on the web available for reading. The other vehicle I own has a turbo, even more critical in propper plug choice. Audi forums are full of good plug general knowledge threads and are very educational.
Bottom line, in Mitsu case, in my experience stock oem worked very well so far. I would stick with it.

 

bosche plugs are terrible. Never ever use them in a mitsu, unless you like misfiring and replacing them frequently.

Use ONLY NGKs (or denso). Factory spec. you wont find a better choice anywhere on the planet.
Dont fall for the rediculous marketing of "splitfire" or "+4"; its all crap.

 

^^^ best post here