I'll put my money on fuel filter blocked or injectors need cleaning. You've done everything else it could be. Go the fuel filter first.
I've only ever run my car ultimate 98 but somehow the filter got block in 10,000ks. My old GLi had done over 40,000ks with no fuel filter change and it was a champion. Luck of the draw I guess when it comes to whether you get a good batch of fuel or a s**t one.

fuel filter is new. economy wise and power wise car is ok. over 600km round town and over 800km on highway. prob not fuel related. the fact that it comes and goes annoys me as i can't just take it somewhere for them to look at as it might be having a good day. could well be that i have purchased a dud lead or plug. thanks for all the replies anyway. if i finally cure it i will post what i did just in case others are having similar dramas

600km around town? I wish i could get anywhere near that with my Fairmont. The best i've ever achieved around town is 420km and on the freeway a little over 500km - in both cases driving like a grandma in economy mode!

for those who may be having similar troubles, i replaced my coil pack on the w/end ( def. not a job u want to be doing too often), and so far everything seems to be fixed. woohoo. idle still not 100% but seems a bit smoother driving and no miss so far. only cost me $30 for coil pack so even though no codes came up (most likely due to incompetent user) i was prepared to pay the cost.

for those s.a. guys in southern area. if u r looking for somewhere to buy cheap second hand parts, as opposed to a wrecker, try falcon spares and repairs (limoscene). always very reasonable.

I am having this problem, well its only the idling problem and i have changed coil, plugs (TWICE), leads, cleaned the isc and throttle body, put in a k&n and still my idle has not changed. I also run on lpg and its notr smooth on that either. I have also had the problem where in cruise and hit the brake to slow down it started accellerating more lol but i checked my brake lights and the switch seems to be ok. any ideas?

i got a simialr prob at the moment, i just had a new brake switch put in, and it still does it, im goin to ford next week and they goin to doa diagnostic on ti and see if the coils are ok, if they are then most likely leads, the plugs are new as well. oh well if its the coils be a good chance to get soem after market ones...

To the user named Prydey,

l previuosly owned a EF XR6 Wagon 5 speed and this vehicle showed very similar symptoms.

i.e. intermitant miss, no real set perameters.

no dought your main problem is that when you take the vehcile to get repaired, the fault will not replicate. It will then not do it for the repairers and then you pick it up it occurs again!!!?

l stuggled on this problem for over 12 months with no result.

l replaced just about everything you could imagin and cleaned, inspected and tested every component in the engine bay, computer loom, fuel tank.

The fault appears to go away for a while, sometimes up to 1000 km but comes back again.

Components l replaced include, ECU ( twice),coil pack ( twice), fuel filter ( twice), leads (twice), spark plugs, cleaned injectors (removed and sent away), compression, fuel pump and so on.

This still did not fix it.

This fault appears that it is not fuel related due to the fact that mileage is excellent (our XR6 Wagon got similar mileage to yours).
Its appears electrical, which is partly correct.

Finally after speaking to a good friend and highly experienced mechanic, he informed me of a similar fault occuring to his father in laws EL.
He ran this vehicle on a dyno for 8 hr to try and replicate the fault, eventually it did and it found that the cause of the problem was a faulty fuel pump relay.

Further testing showed that when the fault occur, there was a noticeable drop in fuel pressure in the fuel rail and the fuel pump voltage became erratic.

So with this component changed and hundreds of dollars wasted for a $10 dollar relay, it realy does show that one really need to go back to the basics when fault diagnosing.

Unfortunately l do not own this vehicile anymore , but l hope this information helps you out.

Regards Leigh.

thanks mate. 2 wks on from replacing coil pack it has not missed although idle is still not 100%. on very low throttle percentage on take off it did splutter a bit so maybe the prob is still there but better spark is masking it more. if the relay is only $10 (even $50) i think i will replace it anyway and see what happens.

i have the same problem with my ef xr6 5spd sedan where sometimes you give it to it if sounds like it is fueling up and gives out black smoke when doing so.
it does it mostly under load.
it only does it up to 50% of the time which if it was plugs,leads or electrical it would more than likely do it all the time.

it does give good economy and has alot of grunt(spins 1st and huge chirp to 2nd both wheels)

anyway talking to a racq roadside repair mechanic to which he pulled out his books and went through with me.
what it said was common was that a vac hose would start leaking or come of of the fuel reg and would cause these probs.(i do have this vac his inside cabin that stops about 30 sec's after engine shut off) does anybody know where the reg is would it be the hiss in side the cabin?

haven't checked where hiss is coming from yet but will let you know.

i personally was thinking throttle position or o2 sensor because if you back off and hit it(throttle) again it would clear.

Same problem with a faulty brake switch. Cruise also works with a pressure switch off the brake booster.

Consider that some of these idle problems could also be head gasket related or incorrect advance from faulty coolant sensor output.

ok i have a siimilar prob to what most of you have. I.E. bad idle but smooth driving (incrdiably smooth). We found that the no. 3 cyclinder is stuffed. We found this out by at idle, we unplugged the injector cables one by one. If the cyclinder is correct then the idle SHOULD drop. If it doesn't then that cyclinder is playing up. Hope this helps