Erratic Idling?

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FrankCastle

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So my Toyota has decided to switch off when I come to a stop and this is what I've discovered thus far:


When I first start it up it idles at about 2000 until the engine has warmed up.
At this point the idling drops and becomes erratic 'hunting' between 500 and 750 revs.
I have to keep the vehicle revving when I slow down to prevent it from switching off.



Google suggests Throttle body so I took it out stripped the IAC and gave it a good clean with carb cleaner but no change.

I even removed the MAF sensor and gave it a good spray.Disconnecting this unit while the car is running stalls it.

Other areas of concern could be fuel pump, ignition coils, vacuum leak or IAC could be faulty.

Is there anything else I could try?
 
While it's of no help to me, perhaps specify model and year of the car?

My Uno had issues with the engine just randomly dying, no matter what the temprature was. Turned out the Fuel pump wasn't giving enough fuel. Replaced it with an electric one that sort of "force fed" the engine.

Wasted so much time on that issue. My father solved that problem for me :P
 
DrYes said:
So my Toyota has decided to switch off when I come to a stop and this is what I've discovered thus far:


When I first start it up it idles at about 2000 until the engine has warmed up.
At this point the idling drops and becomes erratic 'hunting' between 500 and 750 revs.
I have to keep the vehicle revving when I slow down to prevent it from switching off.



Google suggests Throttle body so I took it out stripped the IAC and gave it a good clean with carb cleaner but no change.

I even removed the MAF sensor and gave it a good spray.Disconnecting this unit while the car is running stalls it.

Other areas of concern could be fuel pump, ignition coils, vacuum leak or IAC could be faulty.

Is there anything else I could try?
Click to expand...

My old Camry did this, something oil related when I had the car serviced at my mechanic.
 
Your airflow meter is borked.

The air to fuel ratio then gets messed up and you sit with this. When it does it, switch the car off and leave it for a few minutes then start it again. Should be fine then. If not it's busted beyond return already and needs to be replaced.
 
Pitbull said:
Your airflow meter is borked.

The air to fuel ratio then gets messed up and you sit with this. When it does it, switch the car off and leave it for a few minutes then start it again. Should be fine then. If not it's busted beyond return already and needs to be replaced.
Click to expand...

this is exactly what I sometimes get with my kia picanto, it doesn't do it often but when it does its at the worst times possible.
and I fix it in exactly the same way (turn it off wait a few min and then turn it back on)

my car does though have a cone filter on it, could that affect it?
 
eg2505 said:
this is exactly what I sometimes get with my kia picanto, it doesn't do it often but when it does its at the worst times possible.
and I fix it in exactly the same way (turn it off wait a few min and then turn it back on)

my car does though have a cone filter on it, could that affect it?
Click to expand...

Pretty sure it would yes. There is an adaptor one buys for the cone filters to prevent it. If not just have the air flow meter set at a dealership with the cone filter on. Should not be a problem. Might not even charge you. call them and ask.
 
Same thing happened to my Honda last week. My go to mechanic told me my carb was done for. Found it weird since I had it serviced last year (the carb).

Took it to my dads mechanic and he said the idle jets just needs to be cleaned. Hopefully I'm getting my car today.
 
Pitbull said:
Pretty sure it would yes. There is an adaptor one buys for the cone filters to prevent it. If not just have the air flow meter set at a dealership with the cone filter on. Should not be a problem. Might not even charge you. call them and ask.
Click to expand...

im actually not sure if I have an airflow meter? my check engine light is constantly on and after getting the codes read,
I get these codes;

p0122,P0032,P0134

I checked on the net and the one is related to the ho2s, and somebody also said its the mair flow sensor that is missing,

or am I interpreting my codes wrong?
 
Is there no metal flanch before the air goes into the intake manifold? Normally has an electronic "plug" on it with wires.
 
Last edited:
I think it has such a thing, there is a sensor on the throttle body,
and the cone filter is right next to it, so I do have one then?

engine bay is small though and my filter is facing the wrong way, could that cause things like this?
 
eg2505 said:
I think it has such a thing, there is a sensor on the throttle body,
and the cone filter is right next to it, so I do have one then?

engine bay is small though and my filter is facing the wrong way, could that cause things like this?
Click to expand...

Yea that is the Air flow meter.

Not so much where it's facing. The thing with cone filters are they let in more air as opposed to the normal air filter system. What this is doing now is your air flow meter registers the air coming in and then compensates it with more fuel. When your vehicle dies suddenly you end up with mixture being messed up, either too little fuel too much air or too much fuel too little air. The air flow meter just needs to be set accordingly or deactivated completely.

I would rather have a mechainc explain it to you and set it. Like I said, prob won't even charge you.
 
Check your pcv valve for erratic idling. Had this issue a few months back. Replaced it myself. Problem sorted.

The PCV system is relatively simple. An inlet hose connects to a filtered air source. This is used to supply clean air that is drawn though of the engine. Most of the time this air is supplied through the engine air filter. On a few designs there is a separate inlet filter that cleans the incoming air for the PCV system only.
Click to expand...
 
Pitbull said:
Yea that is the Air flow meter.

Not so much where it's facing. The thing with cone filters are they let in more air as opposed to the normal air filter system. What this is doing now is your air flow meter registers the air coming in and then compensates it with more fuel. When your vehicle dies suddenly you end up with mixture being messed up, either too little fuel too much air or too much fuel too little air. The air flow meter just needs to be set accordingly or deactivated completely.

I would rather have a mechainc explain it to you and set it. Like I said, prob won't even charge you.
Click to expand...

thanks, I do understand, I will check with a dealer , but im not 100% sure they will do it? especially for free,

also what exactly do I need to ask them? and wont they tell me you must fix your check engine light first?
and what about out my codes I got, any of them got anything to do with this issue?

the one mechanic who got me the codes said definitely.
 
eg2505 said:
thanks, I do understand, I will check with a dealer , but im not 100% sure they will do it? especially for free,

also what exactly do I need to ask them? and wont they tell me you must fix your check engine light first?
and what about out my codes I got, any of them got anything to do with this issue?

the one mechanic who got me the codes said definitely.
Click to expand...

Maybe don't take it to the dealership then. I'm sure any mechanical workshop will be able to set your Airflow meter or bypass it. I would take it to a dealership though just to be safe. Maybe sort out the engine warning light at the same time avoid any other future issues.
 
Pitbull said:
Maybe don't take it to the dealership then. I'm sure any mechanical workshop will be able to set your Airflow meter or bypass it. I would take it to a dealership though just to be safe. Maybe sort out the engine warning light at the same time avoid any other future issues.
Click to expand...

dealership wanted to charge me R850 to maybe sort our my check engine light, so definitely no,

one bosch service centre I dealt with quoted me free for the codes but 750 p/h to try and sort out the check engine light,
with no guarantee that they will get it sorted with the custom exhaust on my car, as it dosent have the correct sensors for the ECU

so what do I need to ask for exactly? airflow meter adjustment?
or is there a more technical term they would understand?:D

also could it be this crankshaft pulley bolt issue "plaguing" kia's? is causing this issue? where would I check if its under guarantee/recall and then they must fix it.

thanks again for all your help pitbull, I do appreciate it, and sorry for all the questions
Im a real noob when it comes to cars.:D
 
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