Stalling

[GreenRunner]

I have a 99 4runner with 110,000 miles. Recently it started to act like it was going to stall out after about two miles driving. It doesn't actually stall but goes to aroun 500 rpm. After about 30 seconds of doing this it runs fine and has normal power. It doesn't do it all the time either. I have changed the fuel filter. Checked the PVC valve. I have a K&N air filter on it that I cleaned. I had the muffler changed about 3 months ago.

Any suggestions?

 

[toto]

My first thought is to check your Mass Air Flow (MAF) sensor. It may need cleaning or replacement.

 

[GreenRunner]

I replaced the MAF a few years ago and when it the CEL went on. The CEL doesn't go on at all even when goes into the "stall'.

 

[swimmer2361]

maybe a O2 sensor

 

[GreenRunner]

It is weird it doesn't stall if I let it warm up. That is why it has been trouble to diagnois.