I give up!! Au missing at idle drives ok.
 

Hi just wondering if anyone can help me. My AUII is missing at idle in gear and out. When I slow at the lights and it changes back to first it gives a shudder and the idles drop to about 400rpm. It doesnt do so every time but 60 percent of the time. Someone suggested it was the idle step up motor which I have had replaced( the car idles in gear at 500 to 600rpms) it has made no difference at all except idling in gear is a bit higher. We have done plugs, leads (just had the fuel regulator replaced cos it was overfueling).The longer you sit waiting at lights etc the worse the miss gets but normal driving the car is fine. Fords have said they cant find anything wrong. I dont know what else to do! :yelrotflm

have the mechanics pluged in the diagnostic scanner?
there should be a fault code showing up. might be the map sensor but at $150 + you don't want to change it unless you know

A vacuum leak will normally only show up at idle, check your inlet manifold gasket for leaks or even just vacuum lines fallen off/broken

have u gave throttle body and ISC a very good clean?

Thanx everyone for the info I will have hubby onto it this weekend. And yes Ford have plugged it in and says theres nothing wrong and everything is within specifications. :dance:

Would the O2 sensor cause any of these problems? I would think especially with a previous overfueling issue that the sensor could be shagged.

Which reminds me... I must get that replaced.

Here is an answer from a mechanic to a question asking whether a faulty oxygen sensor could cause poor idling;

Oxygen sensors read the fuel mixture in the exhaust and send the information to the computer. The computer then adjusts the fuel mixture. By not replacing faulty oxygen sensors, you can expect erratic idle and poor running. Your car probably will not quit running but there could be damage to the catalytic converter

I don't know how many K's you car has travelled, but it wouldn't hurt to fit a new oxygen sensor anyway. You've nothing to lose and they do have a use by date.

faulty O2 sensor would show up on the scan tool

What about cleaning the throttle body?

Cleaning Throttle Body
http://www.fordforums.com.au/showpos...2&postcount=48

GK

mine is teh same.

ive done leads, plugs, ISC, throttle body, reset ecu and base idle, but still idles sh/t. drives good though.

mines the same also reversing out of drive way and slight steer it shudders when just idling out and pull up at lights a vibration,

Fuel pump, fuel filter, injectors???

Hahaha... Seems like one of those phantom AU problems...


I have the exact same thing... Tried everything! Even replaced all my injectors...

mine only started doing that after i used the flash tuner... car runs like a dream tho.. seems to be doing it less and less tho

Should it also trigger the engine warning light in the instrument cluster? I've been chasing an AU phantom for ages, have noticed that idle smells rich ATM. Just disconnected the HEGO (O2) sensor altogether and the car starts and runs exactly as per usual. The $15K Korean s**tbox I used for a work car 10 years ago had the "stop engine" light come on when the "servicing" dealer left its HEGO sensor disconnected.

Would someone mind disconnecting their O2 sensor long enough to run their car up to operating temp and post back what happens?

TIA,
Tony.

Are the grounds ok?

NFI. How do I check them?

On second thoughts... a grounding problem would cause the speedo needle to shadow the tacho needle while giving the throttle a blip in Park? So how do I go about finding where the problem is?

If the o2 sensor totally failed it would cause the eng light to come on, but they don't normally totally fail, they get very slow in their operation, which means, although they may not be operating correctly, they are still sending a signal to the ECU (although it is the wrong signal for what is actually occuring), the ECU does not recognise there is a problem so the light stays off.

If the o2 was left unplugged it will cause the light to come on, but maybe not immediatley, as the ECU does testing of all it's sensors by doing a test cycle called a trip. Different manufacturers have different trips and different sensors have different trips.

Basically a trip is a test cycle the ECU looks for, ie the car may have to run at operating temp for 5 minutes and in thet time perform x amount off accelration cyles and do a road speed of x amount (purely speclative cycle) for the ECU to determine whether the sensor is working correctly.

Hmmmmm. Just took the car around the block twice (20 minutes / 26 km) with the O2 sensor disconnected. No red light, no LHM, just drove exactly as it has for ages. It was prewarmed too, I had it idling for 1/2 hr with the sensor unplugged before reading ratter's post, hoping to get it into closed loop and throw an error.

Not sure whether I drove it long enough to self-test, but surely going into closed loop and getting no O2 reading would cause a problem?

Have had issues of spontaneous stalling / immobilisation over the last 6-8 mths or so with no DTC's to give any clue. The bloke I get to scan it thinks there may be some dodgy wiring (he hates afermarket LPG installs, J3 chips etc). Sounds like the PCM may be getting a voltage on the O2 input that's coming from somewhere else via a dodgy joint or worn insulation?

This might give a sparky a starting point. I'd hate to take it to a sparky and have to say "check the entire engine bay and dashboard looms and all the sensors". Would cost a bit unless he was lucky.

Well got my dad to clean the throttle body but it made no difference. Then he put the idles up so it idles in park at 750-800rpm. Now in gear with my foot on the brake it idles at 650rpms. Now it doesnt stall when I come to a stop at lights etc. Hooray!! Still has a slight miss intermittently when idling in gear but I suppose I will have to live with that. At least it doesnt stall now!!

probably a long shot but coil packs might be worth closer inspection, how many k`s has the car done??

my car has only just ticked over 140 000. hmmm ill get some injector cleaner soon. but the injectors arnt ticking so i doubt they are that dirty.

I had a coilpack start to play up ... and it was noticeable at idle ... but also played up while cruising and under load as well. It ended up being one of the terminals on the coilpack deteriorating ... but I would have though it could have caused issues while driving as well.

also being an EGAS model ... getting it to miss under load (ie: one hell of a decent backfire) scared the crap out of the cabbie driving next to me (no damage to the intake thank goodness).

It maybe a vacuum leak as mentioned (should have able to hear a sucking sound from the intake manifold usually) ... another thing it might be is the power steering switch ... this can cause issues with erratic and low idle too (someone mentioned a grinding sound as well).

My car has only done 110,000kms. Heaps better to drive today only missed twice while waiting at the lights. Thanks everyone for your input. Much appreciated!!!!!

My car has done 85,000km and started to miss occasionally at idle about a month ago. Has anyone licked this issue yet?

At the end of March I'm moving to Qld from Tassie and will be driving up towing my 4.55 metre boat. I don't want any hassles en route. I have had all the plugs and leads changed, had the injectors cleaned but nothing changes it. :nothappy: :nothappy:

I noticed that it occurs less frequently with the air con on - probably because of the higher idle speed.

sorry for thread mining but just noticed this response . you should never adjust the base idle it factory preset . if this fixed it i would say your ics is faulty

Are you using a high flow air filter?
UK

manifold gaskets tend to crack and split.. this causes a leak at idle giving a rough idle... Use some CRC / water hell anything and spray it over the manifold where its bolted to the head.. if u hear a loud hissing or it runs differntly then thats ya prob.. i

I've had a rough idle, but fine when driving issue.. an LPG conversion has fixed it. I can only put it down to something related to the petrol system.. Injector, pump, filter?

EDIT: If I switch back to petrol it idles rough as always, but LPG is nice and smooth.

you have dirty injectors

No I'm not UK.

Thanks Injected_250. I'll give it a try - or get my mechanic to. I'm searching for things for them to try I guess.

They gave them a "purge" last August during a service. You think it would be that Ratter?

At the service they did in January, they hooked up the computer and it didn't return any faults.

What a pain. The damn thing drives beautifully but I hate having things like this :nothappy: :nothappy:

OK thats me out. I found that a stock filter gives a better idea at times

UK

If the car is ok on gas, the only difference is the fuel system, so the problem points to petrol, as it is only an idle problem I would say it is injectors as fuel pump or supply problems get worse as revs increase when the demand for fuel flow is greater.
Dirty or leaking injectors do not show up any codes.

AU's tend to get loosening of the inlet manifold bolts, which gives the same sort of symptoms as a buggered inlet gasket, so it's worth getting a size 10 spanner and giving the ones you can get to a good tightening.

and that problem would show on both fuels

Mine starting doing this when I got an aftermarket exhaust. Haven't been able to work it out yet. I've replaced the coil pack, oxy sensor, plugs and leads so I know they aren't involved.

Re: I give up!! Au missing at idle drives ok.
 

I was about to say adjust the throttle body stop screw like I did and for me it stopped the rev hang when stopping and all the hesitation disappeared just from a little turn of a screw....after all the new components I replaced ISC TPS coil packs leads plugs hahaha for me it was just a 1/4 turn of the stop screw and she idles and drives beautifully now..
Anyway going to go and check myself into a mental institution now my brain is fried.

Re: I give up!! Au missing at idle drives ok.
 

That's not really a fix it is just masking the issue and will cause increased fuel consumption and accelerated engine wear (washed bored from over-fueling at idle). It is very likely, as others have said, a vacuum leak in the inlet manifold gasket. Check for vacuum leaks particularly at the inlet manifold the bottom of number 1 and 6 where the inlet manifold mates with the head both when the engine is hot and cold. Use a length of windscreen washer sized hose with one end in the ear to listen for the telltale sucking noise of a vacuum leak while poking around under the manifold at idle. Note the pre fuel injection trick of using engine start sprays etc will often not work to find these leaks as the ECU rapidly adjust for the change in air in the mixture and it's hard to pick up any change in the engine noise or rpms. Just tightening the manifold fasteners usually won't fix it as a small piece of the gasket at the lower part of the inlet port usually burns through once the nuts have become loose.
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Re: I give up!! Au missing at idle drives ok.
 

my au xr6 hesitates at idle and runs perfect i squirted soapy water around the rear of engine between the gap in the inlet manifold and it instantly ran on 5 cyclinders. whats going on ?

Re: I give up!! Au missing at idle drives ok.
 

Looks like you've found a vacuum leak.
If you weren't looking for a vacuum leak.
Why would you be squirting soapy water on the engine?
What did you expect to happen?

Re: I give up!! Au missing at idle drives ok.
 

someone mentioned inlet manifold leak and said to use soapy water in a squirt bottle im hoping its an leaking injector.at least i can tell the mech what i did when he comes to pick the car up once before ive degreased the engine and hosed it off with no problems

Re: I give up!! Au missing at idle drives ok.
 

Why would you be hoping it is a leaking injector when everything points to a broken inlet manifold gasket?

An inlet manifold gasket is a lot cheaper and easier to fix being a $25 job and takes about an hour to replace if you don't know what you are doing.

Re: I give up!! Au missing at idle drives ok.
 

thanks. thats great news i thought it was the other way around i drove it today and it was good. no problem but i know it will re surface iread that the gasket is a common fault