Hi guys and gals, I need some advice with spark plugs in my '93 TR v6. I don't have any problem physically replacing them, (blessed by being skinny And having small hands). My problem is that they only last approx 2000 kms before the car starts misfiring, farting at the lights and losing power on hills. I used the same type as came out- BPR-6ES-11.
It only had normal plugs in the rear, not iridium. Is there any reason other than difficulty of replacement to use the more expensive ones? Or, is there a different type of normal plug that may last me longer? I dont want to spend a small fortune on plugs if they're only going to wear out as fast as the regular ones.
Thanks in advance,
dumb blonde.

No real performance advantage to using a similar geometry iridium plug than your standard plugs, only in terms of replacement scheduling.

What colour do the plugs come out like? fuel fouled? you may have an overfueling issue which is coating the plugs. Any build up?

They come out clean. In fact, they don't appear to have any wear at all on them. Nice grey colour, no deposits. I was wondering if heat might be the cause of them breaking down. I'm not even sure they are the right ones for the car, as I don't have a handbook or workshop manual for it.

http://www.lisho.net/?page_id=3

its a pdf choose second gen

plugs ...go for iridiums for the rear bank

how do the leads and cap look'

raise the bonnet at dark night with the motor running
look for arcs or sparkles

Have you pulled your distributor cap off and checked that ? I recently had a V6 TR in at work with misfire, bad acceleration, bad hill climb etc. It turned out to be a completly buggered distributor cap

NGK BP6ES-11 is the correct plug for the TS. They should last for at least 40,000 km. Misfire can also come from a plug lead that has gone high in resistance, or distributor cap worn out as suggested above.

BPR-6ES-11 plugs may have an internal resistor to suppress radio noise, you need non resistor BP6ES as the spark plug leads already do this.

Go to the NGK website to verify this, but I bet if you change your plugs to the NGK BP6ES-11 you misfire will go away.

Just checked, the extra "R" in the name denotes the plug has an internal resistor. Resistance in leads + resistor in plug = misfire.

PS TR/TS rear bank came with copper plugs from the factory, not a problem if they last for 40K Km in a healthy engine. Not too hard to get to.

Thanks guys, I'll repace with a set of non-resistor plugs and let you know what happens.

Ok, car now has new,non-resistor plugs in it AND a new set of Bosch leads (mr d.b. pulled one off and managed to leave the little metal thingo from the lead on the plug).
It was an ill wind however as we discovered at superbeep that it didn't have the correct leads on anyway.
Unfortunately, these replacements have had little effect on the surging.
What do I check next? The distributor and rotor button?
Thanks.

Ok, car now has new,non-resistor plugs in it AND a new set of Bosch leads (mr d.b. pulled one off and managed to leave the little metal thingo from the lead on the plug).
It was an ill wind however as we discovered at superbeep that it didn't have the correct leads on anyway.
Unfortunately, these replacements have had little effect on the surging.
What do I check next? The distributor and rotor button?
Thanks.

If it's a misfiring problem, Get the ignition coil checked out as well. They can work fine one moment and then break down as they heat up, or under load.

Ok, I've looked at the dizzy cap and noticed that the contact points on the inside are not flat but slightly curved. (But not grooved). The rotor button's "teeth" vary from pointy on the side to very blunt (as in half the height of the outside teeth) in the centre of the section that contacts the inside of the cap. Are these normal, acceptable wear or are they in need of replacement? I've cleaned the metal bits off and its improved slightly.
thanks.

Ok, I've looked at the dizzy cap and noticed that the contact points on the inside are not flat but slightly curved. (But not grooved). The rotor button's "teeth" vary from pointy on the side to very blunt (as in half the height of the outside teeth) in the centre of the section that contacts the inside of the cap. Are these normal, acceptable wear or are they in need of replacement? I've cleaned the metal bits off and its improved slightly.
thanks.

Also look for cracks in the plastic cap, and make sure the sprung carbon tip is making good contact with rotor button. If in doubt, chuck it out.

The sprung tip has lots of tension, and cracks were the first thing I looked for lol. All appears to be normal apart from the wear I previously mentioned.