Slow, weak idle after replacing thermostat (2002 Camry)

[mikekal]

Hi everyone,
I replaced the thermostat on my 2002 Camry today, (YEA!!!!).

This is the first repair I have attempted, (tired of paying someone else for routine maintainance!)

Now the car has a very weak Idle!

I carefully labeled all vacuum hoses when taking the air intake assmby. off, so I don't think this could be the problem.

Any suggestions on what to do??

[AlmightyCamry777]

Changing the thermostat has absolutely no effect on idle, as i am sure you probably know. I'm guessing you knocked an electrical connector loose or forgot to plug something back in, or misrouted a vacuum line.

[mikekal]

Thanks Mighty,

I will backtrack in the AM, looking for any loose connections.

Thought I was being really carefull, but the proof is in the idle.

[Glenn8963]

changing the thermostat may not (initially) caused this, but a note here, did you make sure the car "burped out" any air in the system? if the coolant cannot circulate, you will have an air pocket. this CAN cause erratic behavior. idle the car (at high idle) for a few minutes to make sure the thermostat opens, and the coolant circulates(leave the radiator cap off). it was known for a while that nissans (yeah, i know, this is a toyota forum) had to be slightly raised at the front, to allow the trapped air to come up to the surface (radiator opening). some cars take a very long time to "burp out" any trapped air in the cooling system. so let's say for instance you have trapped air (an air bubble), that is preventing the coolant sensors to communicate back to the computer, giving the computer the wrong commands to work with, which now, can be a cause for the idle you are getting. although i have forgotten much in the way of repairs over the years, in computer terms, it was known as "open loop", and "closed loop" operation. your car "might be" in the open loop phase. but someone who is more up to date than i can say for sure.

[mikekal]

Hi Glenn,

I did run the engine for some time with the rad. cap off, (this is messy!), and also squeezed the upper rad. hose to help 'burp' the system. The hose was hot, which I was told was an indicator that the system may have ran for a sufficient time.?

Since my last post, I read that cleaning the throttle body may help.
Well, my wonderful wife made a trip to O'Reily's and returned with the Shop Size can of Gumout. I used a large amount of the foul smelling stuff, re'assemble the throttle assmby. and started the car; revving it for about 2-3 mins. I repeated this 3 times.

Problem solved!

She idles smoothly again, and drives just like a dream!

Well, this makes one succsessful, (albeit lenghtly) repair.

I look forward to continuing to doing my own maintainance, as needed in the future.

You can bet I'll be in touch with all of you.

Thanks everyone!