AC idle drop, sometimes stalls

[blue62]

Originally Posted by PLP

How long would a used one last?

Is there anything else that may cause the unstable idle?

The three things that I can think of off the top of my head are.

Vacuum leak.
Faulty MAF sensor... or related wiring
Faulty ICV.... or related wiring

I am sure there are more things:

[PLP]

Originally Posted by blue62

The three things that I can think of off the top of my head are.

Vacuum leak.
Faulty MAF sensor... or related wiring
Faulty ICV.... or related wiring

I am sure there are more things:

Sure, many things could be a problem, but if the car starts just fine, has the power, runs smoothly, and only has idle issues, especially at AC load, then what could that narrow down to?

Again, if I let the RPM drop quickly, then it has tendency to stall. If I do it gently (engine braking down to close to idle) it will dive, but recovers and stays OK.

[blue62]

Originally Posted by PLP

Sure, many things could be a problem, but if the car starts just fine, has the power, runs smoothly, and only has idle issues, especially at AC load, then what could that narrow down to?

Again, if I let the RPM drop quickly, then it has tendency to stall. If I do it gently (engine braking down to close to idle) it will dive, but recovers and stays OK.

The three things I listed is where I would start.

[PLP]

Originally Posted by blue62

The three things I listed is where I would start.

Yup, I will get to it. Does not seem to be pressing issue... I rather need to take care of my daily and tire low pressure

Anyway, why I asked was due to the fact that I experience issues at idle under load. If I do not see (or I am just believing I do not...) issues elsewhere, I was trying to justify MAF issues and related. If the MAF was filthy, clogged, wouldn't it exhibit problems elsewhere?

Vacuum leak - under load/higher rpm, small leak would not be noticeable, so this one makes sense as well.

ICV - it's responsibility is idle only.


Just "brainstorming".

[blue62]

Originally Posted by PLP

Yup, I will get to it. Does not seem to be pressing issue... I rather need to take care of my daily and tire low pressure

Anyway, why I asked was due to the fact that I experience issues at idle under load. If I do not see (or I am just believing I do not...) issues elsewhere, I was trying to justify MAF issues and related. If the MAF was filthy, clogged, wouldn't it exhibit problems elsewhere?

Vacuum leak - under load/higher rpm, small leak would not be noticeable, so this one makes sense as well.

ICV - it's responsibility is idle only.


Just "brainstorming".

Old and very wise rule of automotive trouble shooting:
Always go with the simplest things first.
Then work your way up the diagnostic tree.
So.....
Vacuum test is the simplest of the three in my list you just need a vacuum gauge.
MAF sensor is next.... you can unplug it then take the car for a drive and see if the issue changes.
Wiring can be tested with a Multi Meter.
Last replace the ICV..
Simple.

[PLP]

Originally Posted by blue62

Old and very wise rule of automotive trouble shooting:
Always go with the simplest things first.
Simple.

Very so true. Start with outside and follow inside.
My old story - I was helping my dad to resolve why in his 1982 Passat front parking lights would not work. It just came back from a body shop and both headlights were replaced. Low beams, high beams, fogs - are good. Parking lights - gone. Rear works, though.
Those cars were known for electrical issues. The old style connectors were poor.
I spent 3 hours chasing fuses, relays, connectors. I found that power is delivered to the headlight.
So finally, lets check the light bulbs.
Well, they were never installed.... and once you put them in - all worked just fine.
I spent 3.5 hours doing a 15 minute job. In late fall, in Poland (kind of like Michigan weather...).

Originally Posted by blue62

MAF sensor is next.... you can unplug it then take the car for a drive and see if the issue changes.
Wiring can be tested with a Multi Meter.

So you can just unplug it and drive? It will not scream at me?

[blue62]

Originally Posted by PLP

Very so true. Start with outside and follow inside.
My old story - I was helping my dad to resolve why in his 1982 Passat front parking lights would not work. It just came back from a body shop and both headlights were replaced. Low beams, high beams, fogs - are good. Parking lights - gone. Rear works, though.
Those cars were known for electrical issues. The old style connectors were poor.
I spent 3 hours chasing fuses, relays, connectors. I found that power is delivered to the headlight.
So finally, lets check the light bulbs.
Well, they were never installed.... and once you put them in - all worked just fine.
I spent 3.5 hours doing a 15 minute job. In late fall, in Poland (kind of like Michigan weather...).




So you can just unplug it and drive? It will not scream at me?

It will most likely through a code for the MAF.
But you can just delete it.
When you unplug the MAF the DME reverts to a default fueling strategy as a work around.
So you can use that fact to check MAF funtion.
Your just looking for any change to the issue your having..so unplug it go for short drive turn on the AC and evalute the results.
Then plug the MAF back in and clear the code if any.