Rep Power: 127

The weather here in Canadaland is warming and I've noticed that my idle when up to operating temperature seems lower than usual - about 500 rpm according to the tach (AC not on).

I'm used to having an idle about 700 rpm which feels fine.

The idle is consistent and the tach isn't jumping around but it almost feels like it's about to die sitting at a red light.

No or any issues that i'm aware of other than I will probably need a new battery before next winter.

 
Rep Power: 517

Does it still have fast idle after first cold startup and before it's warmed up?

Idle relearn?

 
Rep Power: 127

Cold start idle is minimum 1000-1200 rpm until warmed up then dips to ~700 normally.

Not sure if related but I started to work nights and generally only drive during cooler times of the night. Computer getting too familiar with night time temperatures and not adjusting correctly?

I've only noticed the low idle driving during the day on my off days.

I found an idle realearn thread on here and will try tomorrow during the day.

 
Rep Power: 517

That tells me the IAC is working, not stuck....

Ya, try a memory dump and relearn, that's free and easy LOL


If the battery is really weak it could be dumping memory during cranking, forgets how to idle

 
Rep Power: 127

Would that usually trigger a ?

Like I said I had the battery load tested by my mechanic last oil change and he said definitely get a new one before next winter - it's just over 4 years old.

I think I will expedite the new battery - I forgot I am also occasionally getting what sounds like an alternator whine with increased rpm at times. Don't want to overwork my alternator I'm pretty sure it has never been replaced

 
Rep Power: 517

Never.

You're supposed to relearn idle anytime the battery is disconnected, and some code reader/scanners can wipe out memory when codes are cleared too.

 
Rep Power: 127

So nothing ever came of this issue until last night.

Went to fire up my car after work and it started rough and the idle was dipping up and down a little but fine after warming up.

Started her up cold this afternoon and started misfiring and shaking violently for a few seconds at high idle - the money light came on a few moments later. Took it to my mechanic and hooked it up to the scanner - only code is a cylinder #2 misfire.

We swapped the coils on the number 2 and 3 cylinder and waiting to see if it misfires again. We're thinking could be bad spark plug, ignition coil or clogged injector.

Any ideas?

 
Rep Power: 517

Missing would sure explain why you get a low idle sometimes.
How's the coolant level? Has the head gasket been done yet?

 
Rep Power: 127

Radiator is full and overflow is 3/4 full between min and max markings.

Original head gasket to my best knowledge.

It always appears to idle low when up to operating temp.