Stumbling, EGR or IAC valve? Coin toss, please help!!!
 

I have a 1995 Camry 4 cylinder. On a warm engine, I start it and when it first fires up it will idle really low like 300 rpm like its barely turning. I step on the gas, it continues to sputter and about 10 seconds later it will come out of it and accelerate fine. Just after doing this the idle shoots up to 1500 rpm for about 7 seconds, and then all of the sudden returns to normal at 750rpm. Sometimes afteward when I put it in drive and step on the gas, it hesitates/stumbles for 2 or 3 seconds and then takes off. It only does these symptoms when the engine is warm. It always starts fine when its cold. The worst part is the problem is intermittent. It will be fine, then on the third stop on a trip I will start it up and it will sputter again. Driving me crazy. I took it to toyota dealership and of course it did not display the symptoms for the tech. Im not getting a CEL, and it is not giving any error codes on the diagnostic. The tech didnt see the symptoms, but he said from what I explain, sounds like it could be either the EGR valve or IAC valve, or a number of other things. Quoted me about 400 dollars to replace each item. Im thinking should I flip a coin and replace one, but I dont want to spend unnessesary money to fix a part thats not broke.Any suggestions? thanks!!

RE: Stumbling, EGR or IAC valve? Coin toss, please help!!!
 

The EGR should be off when engine is idling, if on the engine will boog down, stall and run poorly at low RPM. The EGR recirculates exhaust gas back into the intake, but only at higher engine RPM and MPH. It is all tied into the computer.

The valve operates off of engine vacuum that can be disabled and thus the valve turned off. Find the valve and vaccuum hose(s) runing to it, the remove and plug them. See how the engine runs.

The EGR system has a number of trouble codes that can be displayed including being stuck open. As no codes were stored, wonder if this is the problem.

The IAC valve controls engine idle speed by varing bypass air around the throttle body. The valve body contains a small elelctric motor the opens and closes the valve based on computer inputs.

Often the valve becomes dirty and the result is a slow resonse to computer comands and high/low idle.

Cleaning the valve is common. Remove the air intake hose that leads to the throttle body, once removed look into the body and you should see a rectangular slot at the bottom. This is the air intake for the valve. Obtain a can of throttle body cleaner from an autoparts store. Make sure it is safe to use with 02, A/F sensors and ALSO plastics. The IAC valve body is plastic.

With engine running, spray a little bit of the fluid into the slot, not too much or the engine will die. Keep doing this until the idle start behaving normally (assuming the valve just needs cleaning).

As both of the problems are common, do a Google search. Most Toyota cars (and other manufacturers) use about the same valve design, often you can find sites complete with photos on how to clean the IAC and EGR valves.

RE: Stumbling, EGR or IAC valve? Coin toss, please help!!!
 

IAC Valve Solution:
https://www.camryforums.com/m_3580/tm.htm

RE: Stumbling, EGR or IAC valve? Coin toss, please help!!!
 

Hello, thanks for the replies. I tried the IAC valve cleaning with throttle body spray, I really cleaned it out good and used alot of spray. It did not help the situation. One thing I notice is that when its really cold outside, below 20 f the car runs fine. Its only when the outside temp rises above 30 F I notice it does it more often. I cant figure it out, any other suggestions? I havent gotten to pulling the egr hoses yet to see what that does.

RE: Stumbling, EGR or IAC valve? Coin toss, please help!!!
 

When the engine is acting up try pulling off the vacuum hose to the MAP sensor and see if this changes things.

RE: Stumbling, EGR or IAC valve? Coin toss, please help!!!
 

Hello
I have the same problem on my 94 Camry 201,000 MI. First I cleaned the EGR valve it seemed to help out a bit but the problem was still there, last weekend I removed the throttle body and the ICA from it and cleaned it out and replaced the gasket, still no improvement when it comes to the problem , I am on the same boat that you are in , my problem is exactly the same, I'll be sure to keep checking your posts to see if you figure out anything. I am still tryin to figure out what tolook intowith next.

did you check your ect sensor? its a 20 dollar part that could be causing this

I know this is an old thread but it saved my butt and I thought I would share what worked for me.

I had a very similar issue with my 99 Toyota Camry. After reading a bunch of threads, it seemed the common denominator was the EGR. However, replacing the EGR did not seem to help. Would run fine on initial start then after a few minutes RPM would drop significantly and then die altogether. Next step was IAC. Sprayed the throttle body cleaner in and removed the hose leading off of it so I could see what was coming out. Was a little dirty but nothing really to indicate that it was gunked up. So now I'm checking hoses for cracks or collapses, replaced the PCV valve, and went ahead and replaced the plugs and wires for good measure. I thought it seemed to run a little smoother after that but it still died after a couple minutes warming up.

Then I see at the very end of this thread, "did you check your ect sensor?" I figured, what do I have to lose at this point. Put the new sensor on, started it up and the idle was MUCH better this time. Let it run for about 20 minutes then drove it around and it seems to be good to go!

Thanks for posting back with the fix.