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So the missus VX got some loving - swapped the injectors out no issues.

It typically idles fine. Today she tells me, it was running rough, almost stalling while sat at the lights. Then it came good. Sounds to me like a sticky IAC or something not quite right. The fuel is good in it, all vaccuum lines are up / tight, ran the usual aerostart around everything no vac leaks etc.

I ran the IAC reset proc after doing it, but, its almost like it hasn't reset....

Any thoughts/suggestions?

i had this issue on my vx, turned out to be a intermittent dodgy coil pack, the problem was random, i could drive a day sometimes and it was fine, other times nothing but trouble, i put the coils on my tester and when testing the first post it had problems holding spark at low dwell times that suggested a problem and when testing the problem post ramping the dwell up quickly found it cutout completely where it should have still had spark and to boot i had only tested the coil packs a month before during a checkup so i went changing and checking other things lol, it may not be your issue but something to check, try another whole set from a good car if you can.

Oh the IAC doesn't have a reset procedure though everyone seems to say so, it does a simple step in and out every key on to learn it's 0-255 counts.

re: IAC, no it doesn't. that said, after i changed the injectors the thing would barely run. then it came good. then was shit again, so held it at 3000rpm for the obligitary 10 seconds and it came good? and since then, all good.

i've just been for a 30 min drive and she was fine.

whats odd is that its only started since changing injectors and cleaning the throttle body out / cleaning out the IAC etc. which is wierd ie: thats the only thing i've changed. its also not done it before - only since i touched it. lol.

Check you didn't knock any ignition leads off and they are on the spark plugs properly.
Have a good look over everything you touched and make sure everything looks sweet. Do a quick check for vacuum leaks. That's all you can do.

If it still hasn't played up again then just see how it goes. It's somewhere between very hard and impossible to diagnose an intermittent problem in a logical fashion when it is not playing up. All you can do is make educated guesses as to what it could of been based off previous experience.
Sometimes I have to give cars back to customers at work and let them know I haven't fixed or replaced anything. That probably aren't very happy about it until it's explained that we don't have a crystal ball and we could start replacing things but we can't prove they are faulty and there's a good chance we would replace the wrong things and they would be back even more unhappy.

Another tip I've found works, get someone else to look over it as well. It's amazing what obvious stuff a fresh set of eyes can pick up quickly that the original person may of looked at and not seen 10 times. And then it all makes sense once pointed out to them

psyolent wrote:re: IAC, no it doesn't. that said, after i changed the injectors the thing would barely run. then it came good. then was shit again, so held it at 3000rpm for the obligitary 10 seconds and it came good? and since then, all good.

i've just been for a 30 min drive and she was fine.

whats odd is that its only started since changing injectors and cleaning the throttle body out / cleaning out the IAC etc. which is wierd ie: thats the only thing i've changed. its also not done it before - only since i touched it. lol.

the lines will have to re-pressurize and air locked pass through again, so yes reving it may speedup that process.

The1 wrote:i had this issue on my vx, turned out to be a intermittent dodgy coil pack, the problem was random, i could drive a day sometimes and it was fine, other times nothing but trouble, i put the coils on my tester and when testing the first post it had problems holding spark at low dwell times that suggested a problem and when testing the problem post ramping the dwell up quickly found it cutout completely where it should have still had spark and to boot i had only tested the coil packs a month before during a checkup so i went changing and checking other things lol, it may not be your issue but something to check, try another whole set from a good car if you can.

Oh the IAC doesn't have a reset procedure though everyone seems to say so, it does a simple step in and out every key on to learn it's 0-255 counts.

My Mate's VY had a dodgy coil. replaced it and then few weeks later another went so we replaced the whole set with newish aftermarket units I pulled from a pick a part car.

In both coils failing, they both had the intermittent rough running and poor performance. They did pretty good for 500,000km.

well i've driven it all day today, and not had one issue. i've got a pair of os2 sensors to put in it and ordered a replacement IAC, all of which I don't think are necessary, just to cover all bases (read wife bases)

i tell you what though it sure drives a fucktonne better. The1 can I send you the original injectors to check - interested to see how knackered they were

drove all morning again. zero issues.
she has had the car this arvo. waiting for the verdict.
the replacement IAC is here so will chuck that in. interesting to see how we go.

All done, yep good spark and fuel control makes the world of difference. 500,000km from a coil set is good, most don't last half that, and when tested are still working but don't work at full potential