hey all,

iv noticed that over the last 6 months my engone idle has been getting realy rough, what could the cause of this be, as soon as i put it into drive she is smooth but in park she is shocking. Would that be hte engine mounts or do u guys think it would be something to do with the idle sensor, air flow, or well im not sure what else, i wouldnt mind having it nice and smooth again. I expect a lil but of vibration since i have a 99 but i dunno it is just a lil bit to much for me to like.

thanks

whops my bad, its rough when in drive and idling and she is smooth as a kitten in neutral or park, soz guys my bad.

yeh...............my car also suffers from this annoying vibrating idle...( lol just sounds funny to me when i type it like that)

Im not sure what is the cause of it either!

There have been many threads in regards to this annoying idle phenomenon, albeit with no clear cut solution.......

:cry:

is there any way to raise teh idle speed for the first gear or would that be goinng into troublesome waters, just to raise it up 1/2 a nothch would be sufficient enough to kill the vibrations and im guessin that it is prolly the engine mounts but like hell im chaingin them, it seems like alot of hard work, ty neway

You can raise the idle by simply adjusting the screw on the TB. Though thats usually the way to just cover up a problem, kinda like taking pain killers... doesnt fix anything just hides it for a while.

A rough idle can also be caused by a bad transmission, bad catalytic convertor, bad timing... the list goes on and on.

Welcome to the TH Rough Idle Group. :rant: :bowrofl: .
Mine's been doin it so long that until someone else in the car says something I just sit there enjoying those vibrations :shock: .

I thought that adjusting the screw on the throttle body only affected the idle speed in neutral or park, cause yeah we have adjusted that in thepast to get a nice idle and we have it so she idles at about 800 bich is a lil bit high for me vut it is smooth and when u put it into dfrive the revs drop to abot 700 maybe a lil lower. so i hope that helps. or it could be just that the engine is getting on, it has done 16000k's so yeah she is worked, but i do look after her very well, i do oil changes every 5k and transmission ever 10k filters and i got platnium plugs in her, bout to upgrade leads so there shouldnt be any reason why she would be runing rough but i tell u she is a rocket tho.

I had the same on my TF. I just increased the idle from about 700 to about 800 RPM - like DPack said..this hides the problem...but the roghness is gone so I can live with that.

In my case im assuming its the engine mounts, as one of them from what I know, dont know about the other mounts, is starting to crack, thus im assuming its the cause of the intermittent rough vibrating idle.....

thanks for the help guys ill just have to put up with it, who know the gurls mite like it *wink*

I was gunna say "it's a TH thing".

Check/Clean the PCV, it's probably been 7years without one....

hey the pcv im pretty new when it is cumming to this so where and what is it, how do i clean it and im guessin it shouldnt be to hard to fix but yeah all help is welcome, just as long as i dont need any specilty tools ill be ok if ya step me through it. thanks

Use kero or petrol to clean it - solvents may breakdown the plastics. I used the end of a small flat head nail to carefully scrape out the sludge and a cotton bud to assist.

I too had a KH Verada, which had a rough idle. Smooth at every other part of the rev range, but rough at idle.

I took it too one dealer who suggested it was an idle speed issue, and they promptly adjusted the idle speed. Some improvement, but not what I would expect from the silky 3.5 V6.

I then rang my favourite Mitsu dealer in Warragul. They had their suspisions.

All engine mounts replaced, problem solved. It appears that the TH/KH vehicles have fluid filled mounts, which can leak, and basically the mount looses some of it's vibration absorption ability. All mounts were replaced. The vehicle then went on to do another 80,000kms without a problem.

I hope this helps.

Use kero or petrol to clean it - solvents may breakdown the plastics. I used the end of a small flat head nail to carefully scrape out the sludge and a cotton bud to assist.

Have you had much improvement in idle? or just a bit

hey bud try a carbon clean or clean the carbon deposits inside the throttle body with carbie cleaner etc. when the butterfly is closed their is still ment to be a certain gap to allow air to flow if this gap is closed with carbon the car will idle rough. also may need to adjust tps (throttle position sensor) as this car affect it as well.

Note; the computer will gradually learn and corect these slight problems to a certain extent however if the battery has been disconected the computer will reset to factory specs which can cause this prob as it did in mine. after cleaning the throttle body and adjusting the tps it was all good again

ok cheers guys i will definately clean the pcv and yeah im sure it has never been looked at in the 7 years, also i run my car in premium but ill still run the cleaner through just to make sure, let u giys know how it goes and if not i mite have to shell out for new mounts.

Have you had much improvement in idle? or just a bit
Idle is now very stable even under AC and power steer load.

i just cleaned the pcv, it wasnt too dirty, a lil bit of sludege but i dun think it did very much, but ill have to see how it goes int eh next few days, i just used a screw and a earcleaning bud thing and yeah it seems to be all nice, also cleaned the hole the pcv goes in, that also had a lil bit of gunk, but yeah ill keep ya all posted.