Hi all, still trying to sort out the rough idle in my TF, I noticed the rear spark plug leads have 1997 Marked on them so guess they are still the originals from the factory, the front ones have 2003 marked on them, the car has done 284,000 k's, just wonder has anyone found it was the spark plug leads that causes a rough idle? it runs fine when driving no misses, but idling in drive stopped at the lights its like it has a lumpy cam, lol. Its only a cheap car and didn't want to go to the expense of new leads if its not the cause, it has new plugs and dizzy. So just wondering if anyone has found new spark plug leads has fixed a rough idle?

Cheers

The cost of a fix on a problem car is never related to how much you paid for it in the first place.
It won't be leads, as idle causes the least stress on them. High revs and load would see a misfire if a lead was arcing.

The cost of a fix on a problem car is never related to how much you paid for it in the first place.
It won't be leads, as idle causes the least stress on them. High revs and load would see a misfire if a lead was arcing.

Your first sentence is just your usual bullshit know it all reply, your second sentence is helpful, rather you don't reply to any of my future posts

So just wondering if anyone has found new spark plug leads has fixed a rough idle?

Cheers
Never seen a rough idle fixed by new plug leads.

Cheers

Never seen a rough idle fixed by new plug leads.

Cheers

Cool thanks for your reply, you saved me over a hundred bucks, I'm thinking it maybe the valves, cheers

Do a search on the forum, there's a bunch of rough idle threads as it's a very common issue, unfortunately. Most likely culprit is a throttle body badly in need of a clean, possibly dizzy/cap/rotor problem, leaking or blocked PCV hose(s), dodgy MAF, incorrectly set idle air screw, dodgy ISC, leak in duct between air filter and TB, busted throttle position sensor... um... leaking vacuum hose somewhere... er... faulty coolant temperature sensor... that's about all the usual culprits that come to mind but there's probably a bunch more.

EDIT: If your HT leads are arcing it could potentially cause rough idling, though it'd probably be more of a miss than general roughness (ie low). Run in a dark garage and look for arcing, very common with cheap or dirty leads.

Do a search on the forum, there's a bunch of rough idle threads as it's a very common issue, unfortunately. Most likely culprit is a throttle body badly in need of a clean, possibly dizzy/cap/rotor problem, leaking or blocked PCV hose(s), dodgy MAF, incorrectly set idle air screw, dodgy ISC, leak in duct between air filter and TB, busted throttle position sensor... um... leaking vacuum hose somewhere... er... faulty coolant temperature sensor... that's about all the usual culprits that come to mind but there's probably a bunch more.

EDIT: If your HT leads are arcing it could potentially cause rough idling, though it'd probably be more of a miss than general roughness (ie low). Run in a dark garage and look for arcing, very common with cheap or dirty leads.

Thanks so much for your reply Ensoniq5, I will checkout all what you have stated may cause a bad idle on the weekend. much appreciated, cheers

Your first sentence is just your usual bullshit know it all reply

Oh, touchy! It was said in response to your statement that it was a cheap car, so you want a cheap fix.
It is usually the other way around, the older and cheaper a car is, the more expensive the repairs and upkeep are. That is all.

My 3.0l TF tended to idle roughly and erratically when there was slight load on the engine - usually in reverse, steering lock, AC, etc. Replacing the ISC and a complete clean of the TB including the stepper chamber solved the problem (it is idling slightly too well at the moment). I suspect the new ISC had the greater effect, but a TB clean is certainly cheaper first option.