Greetings all I am kind of new to this forum but I have a question to start things off. I own a 1999 Toyota Camry and when it starts up the RPM seems to increase and go back down (you know it bounces back and forth) when I switch it into reverse the RPM does the same thing but when I am driving it, it doesn't seem to matter at all. I know these details are vague but I thought I would ask. Thanks for your help. - Joe

 

The Intake Air Control valve (IAC) sets the idle speed. Might need cleaning. The internet has many hits on this. Do a search on: cleaning IAC valve 5SFE

 

Thanks a ton. I just notices a hole in the air cleaner hose and I ordered a new one because I figure holes aren't good. do you think that might have somethign to do with it?

 

surely it is! that may need major cleaning...

 

If the large diameter hose, most likely no. You can plug the hole to check.

The revving is called hunting.

Might be the manifold air pressure (MAP) sensor but this is rare.

Try cleaning IAC valve first.

If there is a hole in the large intake hose, check all the other hoses such a vacuum for cracks, holes, etc.

The MAP sensor is typically mounted on the firewall behind and above the engine. It has a small diameter hose and an electrical harness to it. A small, plastic box. Make sure the hose running to it has not been damaged.

 

Thanks for all the advice guys. I really do appreciate it. I will clean the IAC valve TODAY!! and I will check all the hoses for holes or cracks. I have another symtom to add. When the car is in Drive or Park it seems to be fine but when I put it in Reverse the RPM's reeve agressively and then if I don't give it some gas it will just die. Any thoughts? Also will driving the car with these issue do serious damage to it? Thanks again. God bless. - Joe