MAFS causing issue?

[2Gud2BTru]

2001 1mzfe v6 with 218xxx miles on it. Since the cold has recently come in, the car has had some problems
-idle issues where it will bounce up and down (the revs will drop a bit then go back up to where it was at) when warming up and also when in gear such as D or R but not in N.
-MPG was at 26mpg combined but now it is doing 17mpg or 16mpg.
I recently had the MAFS cleaned, cleaned the throttle body, and had two codes of P0300. The code said it was two random misfires. TRAC OFF light came one along as the CEL. While cleaning the TB, I had the negative terminal off the battery and when I turned the car back on the lights were gone and the car seemed to drive back to normal. Next day, it was still having idling issues. No lights though. It was also a cold morning. A couple days later, I took it to my Mech. and he had his car scanner read any codes but nothing came up. No lights have come on since I reset the ECU when cleaning the TB but it still idles funny and it feel slower. I have checked the records of repairs on the car and I did not find anything saying that the MAFS has been replaced.
What is the average lifespan of a MAFS on our cars and would that most likely be the cause of the idling issues and low MPG?
Thanks.

[dinoxor]

Might be the dirty idle air control?

And what did you use to clean your throttle body and mafs?
And don't refer to the tutorial here regarding cleaning your mafs, I think the guy who made it cleaned the connector, not the mafs

[2Gud2BTru]

That's what I thought it was the first time so when I cleaned the TB, I sprayed some of the cleaner into the little hole on the bottom of the TB before the bronze flap. I used the CRC TB cleaner and I made sure it was safe to use on fuel injected cars. My Mech used some CRC MAFS cleaner and when he cleaned it, he took out the airbox top and completely removed the MAFS from the tube and he sprayed air to make sure the entire thing was dry before he put it back in. He sprayed the MAFS with air. Ive searched this forum to see how to actually fully remove the IACV but I was unable to find anything. Pictures would help. All I know is that it is the piece that is connected with two screws to the bottom of the TB.

[dinoxor]

You should check with Toyota nation, I think a member did a diy IAC assembly removal with pictures
If anything, shouldn't your mechanic be able to troubleshoot the problem?

[2Gud2BTru]

Okay, I'll check over there to see how to remove it.
Yes I agree with you he should but when I took it to him with no codes he gave it to me like this "I don't want you to be throwing darts at a board in hopes of something fixing the problem without exactly knowing what is wrong". I respect him enough knowing he didn't to the saleman approach and try to sell me a fix that didn't need to be fixed. I still haven't had any codes or CEL come up and its been about two weeks since I had the CEL the first time. It is still idling funny and "hesitating" or coughing upon acceleration in cold weather. I think any weather below 50 degreesF is when it usually happens. Even when the car is fully warmed up it has hesitation issues but no idling issues like when at a stoplight or slowing down. My mech is gonna order a MAFS to replace mine so I should have it installed in the next week or so.

[dinoxor]

sweet, keep us updated!

[1BADGTS]

2Gud2BTru is correct. I've seen this problem quite a bit. When you clean the throttle body alot of times when cleaning the passage to the IAC you'll break some carbon up in the IAC and it will cause it to stick in weird positions. Very simple to remove and clean out.

[2Gud2BTru]

I am having the new MAFS installed tomorrow and will have more updates if it fixes the idling or if the problem continues. The part itself is $245.00 and I wont be charged for labor since it is a pretty simple job. Hopefully this will fix the idling and hesitation. If not, then I will further look into the complete cleaning of the IACV. Thanks for the advice everyone. I will continue with updates until the problem is fixed.

[2Gud2BTru]

Today the new MAFS was installed. So far so good the idling issues are gone and the acceleration hesitation is gone also. My mech said to drive with the stock air filter for a bit and see if the problem continues with that because since the old MAFS was most likely past its lifetime and with the K&N filter bringing in more air, that too much air with a faulty MAFS may have caused the problems to arise sooner. In about a week I will pop back in the K&N cause I miss the gains it gave me (very little yet fun) and the sound it made. If the idling and hesitation comes back with the K&N then I will have to look into maybe a Injen SRI to bring me the noise I like to hear or just remove a resonator from the exhaust, preferably the mid one

[TheGreenDutch]

change the spark plugs and wires while your at it. I run a k&n drop in and took out my snorkel from the bottom of the airbox and never had a problem. Last time my car acted the way your saying my plugs were fouled and still on the oe wires. keep us updated...peace

[2Gud2BTru]

Okay, I'll do that sometime soon. I also was running the K&N drop in and the snorkel delete. Thanks

[2Gud2BTru]

Update: the new MAFS did not seem to fully fix the problem. Still having idling issues in gear and in park when warming up. Rarely have the hesitation in acceleration. Probably gonna check the spark plugs and wires soon. My MPG did go back up to normal though.

[TheGreenDutch]

before you do plugs swap the coil packs around and see if it does anything

[mdatrdcam]

I'm having this exact same problem in my 01 v6 5spd camry, with 205,000 miles. I have all the same symptoms , weird idling, some acceleration hesitation when i first start moving after the car warms up, and now it's gotten to the point where today it won't even stay running. I can start it and it'll run for a second then it dies. I was wondering if there may some kind of fuel delivery issue that may be causing this to happen? Maybe a fuel pump at the end of it's life , or some component of the fuel system thats dirty? Also when i turned my car off last night I noticed a faint humming coming from the back of the car, just under the trunk and in between the two rear wheels, like something was still running after the car had been shut off. The only thing i could think of was that the fuel pump was still running for some reason. Are you having any of the same issues that i'm having? My car won't even run now!

[2Gud2BTru]

My car hasn't gotten to the point to where it dies like your car. Im not familiar with the engine as much as these guys. But see if its something wit your air intake. Maybe check your throttle body and clean that or even while you are doing that, spray some of the throttle body cleaner into the hole before the flap to clean the Idle Air Control Valve. Another thing your could try is getting some fuel injector cleaner and when you get your car running, put a whole bottle of that into the gas tank before putting gas into the car to clean the fuel injectors. Try PMing the GreenDutch, the guy above your post to get a better answer or help. My car still has he idle and some acceleration hesitation under load or even when pushing it more than 40% throttle. Good luck with your car. Make sure you get the throttle body cleaner that is Fuel Injected safe.