2004 Corolla 110k miles with poor idle

[fozzdesy2001]

Do these cars have an idle air control valve? My '04 Subaru did, and when the IACV started to die it caused these symptoms.

I was thinking the same thing and was amazed at the difference it made when cleaned IACV on my Subies but this Toyota was a no-go for cleaning

If you have the OEM filter setup I would revert back to that and see.

Hook up a scan tool capable of live data, especially fuel trims but of course check for trouble codes while you're at it.

Does it only idle rough with the A/C compressor on? What is the idle RPM?

New to you as-in, have you even put a fresh tank of gas in or might it have sat a while and have old fuel? Might also be worthwhile to put a double dose of fuel injector cleaner in it.

Idle is rougher with the air on not as bad with it off. It's had 3 tanks of gas through it one with Techron. fully warmed fuel trims short -1.6 to 2.3 long 3.1 RPM 792-810 with on short -.8 to 1.6 long 3.1 RPM 792 to 814 temp for both 186F

 

[Dave Hess]

Does it still have the original spark plugs ?

 

[MRC01]

I was thinking the same thing and was amazed at the difference it made when cleaned IACV on my Subies but this Toyota was a no-go for cleaning ...

What does that mean? It has an IACV but you can't clean it? Or that you cleaned it but it didn't fix the problem?
Cleaning the IACV on my old Subie didn't fix its idle problem either. I had to replace the IACV - the old one was clean but just didn't work properly.

 

[fozzdesy2001]

The oil kills the MAF.. I had a 2003 Vibe with the 1ZZFE engine and had a MAF go out due to excessive oil from over oiling the filter .

Same engine, and the K&N filter was NASTY almost dripping with oil, immediately replaced with a Denso that's who makes them for Toyota

 

[fozzdesy2001]

What does that mean? It has an IACV but you can't clean it? Or that you cleaned it but it didn't fix the problem?
Cleaning the IACV on my old Subie didn't fix its idle problem either. I had to replace the IACV - the old one was clean but just didn't work properly.

Cleaning the IACV made no difference for this Toyota.