'97 Camry high/fluctuating Idle-Cant figure it out!

[legolyle]

Alright guys, I have '97 Camry 4 cylinder and I cannot for the life of me figure out why its idling high.
Ive been a lurker on these forums for some time now and am now in desperate need of some help in figuring out why the HECK I cant get the idle down...

So this is my first post, don't be too harsh :P

I've got a high AND fluctuating idle, it used to be mediocre and now its really bad. It started out just as a high 1200ish rpm idle. and it is now a nightmare of revving between 1500 and 2000 RPM Constantly-fluctuating.

Here is what I know/have done so far:

I replaced the IACV (as I thought it was bad-but it wasn't)
I replaced the VSV (which was bad-but it didn't help, heh)
I replaced TPS (cuz it was cheap)
and I also pulled the whole throttle body off, gave it a good cleaning, and re-attached it and replaced the radiator hoses going to it.

I checked the Coolant temp sensor based on the Haynes manuals specs and it checked out fine.

And tonight I pulled the EGR valve off a second time and gave it as good a cleaning as possible-just because I think it needed it done.

Right now it is still idling high and fluctuating. (1500-2000)

BUT what's really weird (but could help me figure out whats wrong) is that when I cover the IAC valve hole in the throttle body, the idle steadies out anywhere between 1500 and 2000. Doesn't fluctuate anymore.

Ive checked/replaced about 1/2 the vacuum hoses, but not the one going to the VSV/EGR system behind the engine-they are a pain to get to.

The only other real cause I can think of is a vacuum leak somewhere in the intake. And I don't know where, and I don't know how it suddenly got there within a few months time.

Right now I'm sort of stumped. The next thing I'm going to try is replacing the EGR valve gaskets and replacing the CTS (the engine also has a pinging noise - CTS or EGR could be possible causes of that).

So if anyone has any suggestions on what I should do here, please let me know!

thanks!

[bigbird]

sounds kinda like my 97 1mz but the idle was low and fluctuating. is there a check engine light?

[ShawnTRD]

I would try resetting the computer. Some say disconnecting the battery for a while will reset it. May only need a minute but I would wait 30 minutes. Others remove the EFI fuse. And I've even see disconnecting the battery for a while and turn the headlights on. I would say disconnect the battery for a while and turn the headlights on, and pull the EFI for 30 minutes. Then hook it all back up start the car and let it idle for a while. See if that helps.

[Mister_Perkins]

Have you checked for vacuum leaks?

Spray some Carb cleaner or Starting fluid around the vacuum lines / injectors / intake and see if the idle changes. If it does you have a vacuum leak somewhere.

[legolyle]

thanks for the responses guys,

I replaced the EGR gasket and the CTS and it didn't do a darn thing.

I will try the computer reset idea and the carb cleaner ideas next and post back what I get.

As for the check engine light: It has one NOW. after I replaced the TPS and cleaned the EGR valve last night, the check engine light came on. I'll get it checked to see what its for. But it didn't have one before.

For the longest time it did have one for the EGR system, but I replaced the VSV a few weeks ago and it went away.

Ill get back to you guys in a bit.

[legolyle]

okay guys I think I found part of the problem.

firstly: in my original post I had said that I had checked the CTS and according to the haynes manual and it had checked out-I mistook the CTS for the CT Sending Unit (right beside the CTS). I actually originally checked the SU and it checked out okay.

earlier when I replaced the CTS, I pulled all the plugs near it to make it easier to get to, and when I did so, the Temperature Sending unit's (right beside the CTS) plug was broken. The insulator around the metal connector inside the plug had broken off and fallen out and i noticed it but didn't think much of it.
A while ago, I decided to test something, I pulled the almost broken covering plug off of the outside of the wire (its a single wire plug) and was left with a connector pin. I insulated the connector pin using a small piece of duct tape wrapped around it. And then plugged it back in without the plastic piece.
I started the engine cold and it began to immediately idle at 1200 rpm. (which is a normal idle for a cold engine). However, as the engine warmed up (according to the temperature gauge) the idle went back up to 2000+ rpm and began fluctuating again.

I'm going to go get a sending unit right now if possible and replace it, and then try it with my duct tape insulated broken plug and see if the sending unit's the problem-even though it checked out okay before.

I tried the carb cleaner idea/computer reset idea, but no luck with either...

Ill get back to you guys soon-if you guys have any idea what it could be by now (lol) please chime in

[legolyle]

Alright, I replaced the CTSU, it had no effect.

The car is currently idling between 2000 and 3000 RPM

It seems very spontaneous, sometimes it'll idle from 1500 to 2000 and now it seems to want to idle btwn 2000 and 3000.

However, when I unplug the IAC the idle steadies out and drops all the way down to 1500ish. I'm beginning to wonder one of two things:

1) there is a leak somewhere in the vacuum I didn't find
and/or
2) the ECU is faulty

I'm going to try and look for a leak again.

edit:

Ive since found that when the car is started cold, and the IAC unplugged/hole covered, that the car idles at around 1500 rpm while warming up and then once it gets warm it will start idling at around 2000+ RPM and fluctuating just a little bit.