spark plugs and ignition coil

[dsulu]

This is a new post regarding some maintenance work I am about embark on. my 98 boxster

Spark Plugs: I got 6 of those NGK BKR-6EK, on the avg, how long do they last under normal driving condition.

Ignition coil: How do I trouble shoot these coils (one per spark plug). besides visual inspection. Can I use multimeter for some resistance testing?

At 116000 miles, while I got the car jacked up and both rear wheels out, should I do additional maintenance based work besides changing the rear brake pads?

Any input is greatly appreciated!

:)

[70Sixter]

Not sure about multimeter, but if a coil fails you will get a code. A failing coil might result in plugs that are more fouled than the good coils.

Good time to change oil and filter if you are due. You might also replace the "lifetime" coolant.

[dsulu]

Thanks!

I noticed that the both right and left cylinder banks, the middle cylinder's spark plug sleeves are coated w/ motor oil.

Wonder why the middle ones failed. Are they subjected to more heat?

I will try to use a brass/rubber boat transom plug to pull that sleeve out the engine. www.pedrosgarage.com/Site_3/Change_Spark_Plugs_%26_Tubes.html

[kbrandsma]

If you are changing the spark plugs at 116K you might as well go to DIY Menu/Maintenance Schedule at the Top of the page and do the entire 120K major tune-up. Lots of things from oil, filters, serpentine belt, etc. At 90 K I replaced my coolant, some hoses, water pump and the thermostat. I recently replace my front motor mount two weeks ago. I wished I would have done that sooner, what a difference!

[dsulu]

Just an update,

I started w/ changing the Bosch FR7 LDC4 plugs to NGK BKR 6EK, as it turned out, I think the NGK plugs are in heat range 6. The engine started misfire/ ran rough.

So I got Bosch plugs FR7 LDC+ (not FR7 LDC4) in now. The engine seems to run smoothly.

So here is the run down.

Kragen's auto: NGK BKR 6EK @ 5.99/each, misfire. Exchange them for Bosch FR7 LDC+ @ 3.99/each.

No problem.

[RFM]

European heat range system (like Bosch) is upwards based: Bosch range 7 is heater than 6 and colder than 8. NGK used the opposite system: NGK range 6 is heater than 7 and colder than 5. So do not compare them in the same way.