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MAF Problem?

winterstorm

winterstorm

New member
i believe this could be a bad maf but no codes are showing up so i dont know. intermittently when i accelerate from a stop my car will stop accelerating maybe around 2500 rpms and the rpms will go down to around a thousand. ill have the pedal to the floor when this happens and the car doesnt go anywhere (its still moving from the momentum it built up beforehand obviously but otherwise no acceleration). then after about 2-4 seconds all of a sudden the car "comes back to life" and hauls @$$ (because i have the pedal to the floor trying to get it to accelerate lol). i believe this is engine hesitation due to a faulty maf. i have cleaned the maf and this issue doesnt occur as often but it still does every once and a while. i thought it was transmission issues for a while because when i roll through a stop sign or even stop completely and put my foot on the gas very quickly it almost feels like something is grinding and then it shifts into gear. i say grinding because it feels like it and it also makes a horrid sound that sounds like grinding. so i just dont kno lol, my car has issues. whose doesnt haha
 


Disconnect the MAF and see how the car drives. It will run rough, but it won't have those fluctuations. When I had a bad MAF the car would die on me unless I kept giving it gas.
 
i mean i wont notice if its not having those problems or not because they are very intermittent, it probly occurs once every couple weeks. would there be any other purpose other than that to drive with the maf unplugged? cuz if there isnt i dont really want to do that haha
 
The only time I drove without it connected was to confirm that it was the problem. The MAF sensor reports to the PCM how the air is and adjusts air and fuel mixes accordingly. Without the MAF connected, it uses a default set of parameters, which allow the car to run, but it will run a bit rough. When mine was bad, the car would die when I idled at a stop light, and then to restart I had to keep giving the car gas.

You said you get a grinding noise. I never had a grinding issue when my MAF was bad, so I don't think it would be that.
 


Matt.. you can drive with it disconnected and the car runs off table data vs actual airflow. Only other way to test this would be to swap the maf. Many times maf won't throw a code.
 


Here is a question because I'm dealing with the same thing ...Tap the MAF with something. When I tap mine the car will just die. I have the same issues as you with the pedal to the metal and nothing happens so that's why your thread interests me. On mine I would just wiggle the MAF sensor harness connector and it would act up, so I replaced it and that did not help. I tapped the MAF and it died , so I suspect it's an internal contact.
My only concern with this diagnosis is the gas pedal issue.
This is just a thought but here is what I'm talking about. When You press the pedal the Throttle sensor reads the amount of pressure you put and that in turn correlates it to how much faster you want to go. If the Throttle sensor does not read the change then it will think you are not pressing the gas so it will not act.
I'm a Lexus tech so I know Japanese cars more than American ( But the throttle body is a Hitachi :th_biggrin2:) so I'm not 100% on how these cars work by design. Usually if you have a bad MAF sensor on a Toyota it will not affect the gas pedal input ( in my experience)
Any way ...TAP your sensor please :th_praying:and tell me if yours dies also.
 
the op kinda seems like what my 04 did when the crank sensor went out of it...

could also be something to do with the drive by wire in the tb.. i have a spare tb, with all the sensors from an 04 if someone wants to make and offer.
 
no, 04+ are drive by wire. 03 and under where cable, if you have a cable one, i can do the test for you, as my 02 has a bad mass air flow, and its trowing a code.
 


no bill haha i dont have the time to during the week im busy with school. and yeah 04+ are all wires no throttle cable which i personally dont like but whatever haha.

so bill how would u suggest cleaning the tb?...never did it before and i see that some people say to take it of some people say you can leave it on. what do i do?
 
Pull off intake tube (2 8mm)
Remove TB (4 10mm)
Spray and clean with TB cleaner.

If this takes you more than 30 minutes..you are doing something wrong.
 
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