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Dan, ASE Certified Technician
Category: Toyota
Satisfied Customers: 1694
Experience:  Auto Technician
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Idle is low. stalls at stop lights. is there a way to adjust

Customer Question

idle is low. stalls at stop lights. is there a way to adjust the idle speed?
JA: Is the check engine light on? Does the car stall at idle or when driving?
Customer: it sometimes stalls when you stop. no light.
JA: What is the model/year of your Toyota?
Customer: 2002 toyota sienna
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: yes. i tried cleaning the IAC and MAF. I used carb cleaner for cleaning the MAF and now I discover there is a different cleaner for that, do not know if that makes a difference.
JA: Anything else you think the mechanic should know?
Customer: not right now
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Toyota Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: Toyota
Expert:  Dan replied 1 year ago.

Pull the intake tube and clean the throttle body and plate. You may have carbon in the throttle body that is restricting the air flow causing your low idle problem.

Please let me know what more I can do to assist you today. Also, please remember to rate my answer, Just Answer does not compensate me for my time and resources. Follow up questions are included in the price of your question. If you are using the free trial, or have a subscription a rating is still required.
Thank you so much!

Customer: replied 1 year ago.
When I said that I had cleaned the IAC, I should have explicitly added that I had cleaned the throttle body as well. You can't really get to clean the IAC without that.
Customer: replied 1 year ago.
Oh ... and my wife said that the A/C is not blowing cold at stop lights as well. I assume it is related since it all happend after I cleaned the IAC, throttle body, and MAF. Does the MAF affect the A/C?
Customer: replied 1 year ago.
Is there a way to just adjust the idle speed? or is it all controlled by the sensors now?
Expert:  Dan replied 1 year ago.

No, the MAF does not affect the AC, No way to adjust idle speed, it is controlled by the IAC valve.

You might have a problem with the AC compressor, if it is binding at idle, it could be causing the idle to drop. You could take off the drive belt and verify all pulleys and accessories are easy to turn by hand.

Customer: replied 1 year ago.
Do you have a diagram that I can use to locate this AC compressor? (note, though, that the AC did not seem to be a problem before I cleaned the IAC, throttle body, and MAF ... also this is just a report from my wife, I have not experienced it myself, so it is a "maybe" symptom... I will drive the van myself tomorrow)How can I tell that, for instance, the IAC is actually bad and not merely in need of cleaning? Can I test with a multitester the way I can with the throttle position sensor?
Customer: replied 1 year ago.
when you think I am straying from what could be considered legitimate follow up questions, let me know ... so far I think I am still trying to diagnose the initial problem with the low idle bearing in mind the steps I have already taken)Also ... this chat window is at work, and I will not be able to read your next response until tomorrow)Thank you.
Expert:  Dan replied 1 year ago.

I use a scan tool to test the IAC valve, you can open and close it with a scan tool and verify idle speed is following. The ac is probably not related, since you said the problem started after cleaning the parts. Are you getting any engine lights on?

Customer: replied 1 year ago.
No check engine light on. Cleaned 'em a second time. I think the A/C is working, my wife hasn't tried it yet. Still requires me to rev the engine (high!) when starting ... but not stalling after it gets going as much as it had been. For me. My wife is the one that seems to bring out the worst in it, so we shall see how it goes when she tries driving it again tomorrow (I had the van today and she had the other car). Still. I should just be able to crank the ignition, apply a little gas, and have it start. I shouldn't have to rev it high and let it settle down, so something still seems "off".
Expert:  Dan replied 1 year ago.

Your Iac valve could be the problem, also check the engine over for any vacuum leaks.

Expert:  Dan replied 1 year ago.

Hello again Dan here,

I am contacting you because the post has not been closed or rated. We have 7 days to get a post rated before it times out. When a post times out, that means it’s no longer on my active list (if you reply I never know it.) You have already paid the fees to get this question answered, but it appears you’re not pleased, or need more help.

Let me help some more. Is there anything else you feel I could offer so you would be pleased with my help. Please use the 5 star rating system at the top of the screen, it would be appreciated. If you feel the need to rate less than 3 stars, please let me know why and what I can do to help you more. I do not get compensated for my time unless you rate me.

Thanks Dan