What is a good spark plug that can be used for Mitsubishi Magna 2003??

It is hard and expensive to change them due to the intake opening for the rear 3 plugs … so what is a long lasting plug that can be fitted and what should be the interval of replacing??

The plugs mitsubishi supply for the rear bank on magnas are supposed to be good for 100,000kms. Not sure of the specs but there's probably an aftermarket equivalent that is cheaper than buying from mitsubishi.

NGK iridium tip spark plugs are popular and are supposed to be good for 60,000kms (from memory). Last time I looked they could be had for around $15/ plug.

If you've got a decent set of tools and some basic mechanical skills - removing the intake plennum yourself is not difficult, just a little time consuming.

The plugs I use are NGK PFR6G-11

These are good for 100k kilometres or 60k miles but I tend to change over a little more often.

For the rears, you will need to remove the top manifold, is not hard, just watch what you are doing so you can put it all back. If in doubt take it to a mechanic

i have got lpg installed about 4 months ago and wanting to replace my plugs i have been told i need higher heat plugs is this correct and which ones i want platinum do you just put in back or in front as well for tj magna

can't really say for LPG-suited plugs - other members here run LPG and will advise I am sure.

Our 3rd Gens come stock with platinum in the rear bank (for longevity, to avoid unbolting the inlet plenum frequently with plug changes). Its relatively easy and cheap to replace the front bank spark plugs, so strictly speaking platinum (etc) long-life plugs there are not required.

HOWEVER, lots of folks bung-in Platinum or Iridium all-round - means no plug changes for approx 100K.... of course, if you go down the 6-plugs do-it-once route - MAKE SURE whoever services your car knows that long-life plugs are in the front also so they don't chuck out your expensive plat/irid plugs and stick standards in, and charge you for the priviledge.

With gas you go 1 heat range cooler.
With NGK plugs the higher the number the cooler the plug.

ngk specifies the same plugs for petrol and LPG

Iridium IX plugs provide a stronger spark but only last 50000km on LPG compared to 60000 on petrol
part# BKR5EIX-11

Laser Iridium last longer 90000Km on LPG compared to 100000km for petrol
part# IFR5E-11

going one stage cooler can cause poor performance in cooler weather when running on petrol
part#'s BKR6EIX-11 and IFR6E-11

i like to fit them all around that way its less work for me

the L-Ir would be also be better when servicing cause you can really strip down the engine every 90000km and do timing belt, rocker cover seals, leads, dizzy cap and plugs and not worry about them for another 90000km

ngk specifies the same plugs for petrol and LPG

Iridium IX plugs provide a stronger spark but only last 50000km on LPG compared to 60000 on petrol
part# BKR5EIX-11

Laser Iridium last longer 90000Km on LPG compared to 100000km for petrol
part# IFR5E-11

going one stage cooler can cause poor performance in cooler weather when running on petrol
part#'s BKR6EIX-11 and IFR6E-11

i like to fit them all around that way its less work for me

the L-Ir would be also be better when servicing cause you can really strip down the engine every 90000km and do timing belt, rocker cover seals, leads, dizzy cap and plugs and not worry about them for another 90000km