HI, Im having a problem with my idle. If i rev my motor up it will rev normally then go down to 1500 for about 10-15 seconds and then go back down to normal.. I cant figure out why it does this...

It doesnt do it all the time but sometimes and its worrying me...

Also, my check engine light will come on randomly and then go off sometimes.. The car doesnt run bad or anything. I cant figure out why it comes on and turns off. Only turns on for less than 1 minute. sometimes only for about 20 seconds....

Any help is greatly appreciated...

 

Pull the codes: https://www.thirdgen.org/service-eng...ht-error-codes

 

Doesnt the check engine light have to stay on to pull the codes?
What are your thoughts about the idle?