Hey guys, I'm having a few issues with the TH and how rough it runs at idle, doesnt seem to have all the power it should either and economy is up a bit(avg of 10.5). Just had major service done at mitsu, and won't be going back there(i won't go into it).

So I've decided as a start, ill change -
Dizzy cap and rotor button,
Back 3 plugs(thought they would've been done by mitsu in a major service, but werent)
and all 6 ignition leads.

What I need to know is what brand, thickness etc of ignition leads I should buy, and if anyone knows what brand and the part number for the platinum(rear) plugs for a 3.5.
I though i'd just do the rest, dizzy/rotor using genuine mitsu parts.

Thanks guys
Luke

Did the rough running only happen after the major service?

Did they change the t/belt? If so, check that they didnt fook the cam timing.

Don't expect big things by changing the leads and plugs over unless they're shot.

Buy the 4$ plugs and change them more often. I'd buy some thicker leads > 8mm as they'll last some time.

fuel inj or filter, dirty throttle body amongst other things could be the problem as well as your ignition system.

Hey guys, I'm having a few issues with the TH and how rough it runs at idle, doesnt seem to have all the power it should either and economy is up a bit(avg of 10.5). Just had major service done at mitsu, and won't be going back there(i won't go into it).

So I've decided as a start, ill change -
Dizzy cap and rotor button,
Back 3 plugs(thought they would've been done by mitsu in a major service, but werent)
and all 6 ignition leads.

What I need to know is what brand, thickness etc of ignition leads I should buy, and if anyone knows what brand and the part number for the platinum(rear) plugs for a 3.5.
I though i'd just do the rest, dizzy/rotor using genuine mitsu parts.

Thanks guys
Luke

just use some ngk plugs and some topgun leads, there decent enough, my TH has a rough idle as well getting a fresh TB with a new ISC on its way so i can let you know if it helps.

EDIT: if you can track down some echlin Ignition cap/rotor they are quite good and resonably priced, but since NP closed they have become pretty hard to track down

ill 2nd the fact its better to just use copper plugs and change them every 10thousand or so instead of going platinums.

leads of at least 8mm thick are best, but dont buy a top gun set, cuz they never quite fit properly, always measure up each of the plugs you currently have and go buy replacements, not much difference in price singley. there is usually 1 or 2 that are either just to short or just too long.

rough idle could be a pleathera of things.

ill 2nd the fact its better to just use copper plugs and change them every 10thousand or so instead of going platinums.

leads of at least 8mm thick are best, but dont buy a top gun set, cuz they never quite fit properly, always measure up each of the plugs you currently have and go buy replacements, not much difference in price singley. there is usually 1 or 2 that are either just to short or just too long.

rough idle could be a pleathera of things.

ive sold zillions of sets of Topgun leads only ever had 1 problem and it was user related (didnt use heatshields on VX leads) ive infact got a set of 3.5l leads sitting at work i can measure them up if you want but im 110% positive they will fit fine.

EDIT: because of the Longer plug cap it will be hard to get them singly, most places just keep the old style ones (old commy and falcon) in singles.

THLAD79,
As GoTRICE said do not expect to fix rough idle by changing cables and plugs.
I also have TH and it has rough idle since I bought it seven years ago. I did change cables,cap, rotor, spark plugs, throttle body and it did not affect idle at all, still the same.

TH has 147 kw, early TJ models have 150 kw (different camshafts and engine management system).
From August 2001 TJ and latter TL/TW models have 155 kw (differently calibrated engine management).

I remember reading someones post that their TL or TW idles smoothly. My guess would be that revised cams and ECU make all the difference.

I used NGK cables RC-ME 108 at $116, but genuine cables are equally good and they cost the same as NGK.
Spark plugs NGK iridium BKR5EIX-11 at $114 for six. They last 60000 km. You can go with platinum NGK PFR5J-11, they are cheaper and will last 100000 km.
Distributor cap Echlin EP931 $65, rotor AU135 $19.
EZ Boy's High Flowed throttle body $134.50, highly recommended :D .

Your average fuel consumption is OK.

The idle might be out also, I changed my battery the other day and the gear changes and idle is so much better. The battery was almost dead, lasted about 3 - 3.5 years.

Rough idle can be a number of things, sus out the fuel injectors/fuel rail. TPS, etc

not being rude but search button has plenty of ideas, suggestions as its a common thing with mitsubishi's, especially autos, which points at the torque convertor or similiar.

My cousin had a verada Xi, very nice, but noticeable idle. Bought a vz/vx calais or something much better.

ok where do i start, it hasn't always idled like this, you can actually hear the miss it has as it sort of splutters, it did do this before the major service also, thanks for all the tips etc guys, as I said doing this stuff is a first step, I bought the car in sept last yr and I'm unsure of the history, so I'd rather do it all anyway.
10.5 imho is shocking for the average, my TF was about 9 with exhaust/extractors etc and my TH sports was about 8.5(manual), so i am unhappy with the economy of this TH. The injectors apparently had a clean(how i dont know) by mitsu in the service. Auto is booked into fluidrive to have a powerflush and checkover next week.

I've never done the back plugs myself on any of my magna's do i require a gasket kit of any type to remove the throttle body? And can you get aftermarket ignition leads with the caps on them as the mitsu ones do?

Thanks again
Luke

I've never done the back plugs myself on any of my magna's do i require a gasket kit of any type to remove the throttle body? And can you get aftermarket ignition leads with the caps on them as the mitsu ones do?

Thanks again
Luke

leave the t/b connected to the inlet manifold and take it off as a whole. New inlet manifold gasket...

thats what i thought, thanks again