1997 MAF code: on roadtrip

[mika]

The more I read, the more confused I get.

I am on a roadtrip and my CEL came on after the car was at a stoplight. It started hunting idle and almost felt like a misfire. The idle is not steady at stop, you can see the tach going up and down. I read the code, and it says "mass airflow sensor." I checked all vacuume lines and they are all intact. I unplugged the MAF sensor, and the idle is still fluctuating.

My question is: if the MAF is bad, and you unplug it, should it immediately start running/idling correctly? Also, in your experience, when the MAF code comes up, how often was the MAF actually bad? The car is drivable once it is moving from a stop. (hx of car: The plugs, wires, and cap are new. The rotor's screws are stripped as I could not remove them, but the rotor looks intact)

[erikv11]

Unplug the MAF with the car off, then start the car. Idle may be unsteady for 30 seconds but then it should flatten out and be fine.

There are some P80 cars where unplugging the MAF doesn't "work" i.e. the car will always run like crap with the MAF unplugged, instead of going into default. I don't know why.

[erikv11]

And about the MAF code, in my experience if the car is well maintained then the problem is usually the MAF itself, otherwise it is usually a vacuum leak.

[cn90]

Unpluggin the MAF --> car runs in Limp Home mode. Yes, it runs like crap but will not stall.

If you happen to be near Omaha, I have a almost-new (1 month old) Bosch MAF sitting around in my garage. PM me if you need it.

[abscate]

The more I read, the more confused I get.

I am on a roadtrip and my CEL came on after the car was at a stoplight. It started hunting idle and almost felt like a misfire. The idle is not steady at stop, you can see the tach going up and down. I read the code, and it says "mass airflow sensor." I checked all vacuume lines and they are all intact. I unplugged the MAF sensor, and the idle is still fluctuating.

My question is: if the MAF is bad, and you unplug it, should it immediately start running/idling correctly? Also, in your experience, when the MAF code comes up, how often was the MAF actually bad? The car is drivable once it is moving from a stop. (hx of car: The plugs, wires, and cap are new. The rotor's screws are stripped as I could not remove them, but the rotor looks intact)

On P80 chassis I would say at least 1/2 of MAF codes are caused by something else, with vacuum leaks being the number one problem

[mika]

The more I read, the more confused I get.

I am on a roadtrip and my CEL came on after the car was at a stoplight. It started hunting idle and almost felt like a misfire. The idle is not steady at stop, you can see the tach going up and down. I read the code, and it says "mass airflow sensor." I checked all vacuume lines and they are all intact. I unplugged the MAF sensor, and the idle is still fluctuating.

My question is: if the MAF is bad, and you unplug it, should it immediately start running/idling correctly? Also, in your experience, when the MAF code comes up, how often was the MAF actually bad? The car is drivable once it is moving from a stop. (hx of car: The plugs, wires, and cap are new. The rotor's screws are stripped as I could not remove them, but the rotor looks intact)

On P80 chassis I would say at least 1/2 of MAF codes are caused by something else, with vacuum leaks being the number one problem

Off the top of your head, what are those other common causes after the vacuum leaks?

[abscate]

If not vacuum leaks, then they usually come with a bunch of other codes from poor running. As noted above, when cars aren't well maintained, they get a bunch of problems which finally the owner notices smoke, fire, brimstone and locusts and then starts posting 'whats wrong with my car'

By this time, you have 10 P codes stored, with usually only one or two of them relevant.

whats the actual P code(s) you are seeing? Never let the AZ guys tell you what the code description is without the actual code. My tester still tells me my P1332 code is a V8 engine error on my T5. I wish.

[erikv11]

Unpluggin the MAF --> car runs in Limp Home mode. Yes, it runs like crap but will not stall.
...

This is not correct. On almost every P80, if you unplug the MAF the ECU goes into a default air:fuel mixture that is rich, but the engine runs well. Almost the only noticeable difference is that the MPG will be low, it doesn't run like crap at all. It is a default mode not a "limp home" mode like the transmission has.

[mika]

to close the subject: With MAF plugged out, car ran slightly better but not much. Threw a different MAF sensor into the car (not the full tube, just the insert) and it ran correct. Thank you for all the help, just needed a new MAF.

In summary :
1) car will not always run better with MAF unplugged
2) you will get a MAF code if the sensor is bad, but not any other codes (if just maf bad)
3) you can swap the insert sensor instead of the full snorkel tube. (ebay, 7$) I used vice grips to unscrew the security torx screws, as I did not have the bit.
4) make sure its not a vacuum leak (obvious)

[xHeart]

...
4) make sure its not a vacuum leak (obvious)

what vacuum leak is likely?