Loose MAF Sensor

My truck has been shifting extra crappy lately and I noticed one of the screws holding the MAF in place was loose and it was rattling around a bit. Could this be causing issues? i plan on removing it and cleaning it anyway as soon as i get some MAF cleaner. 17k miles on the odometer.

 

I don't think it could be the issue?

Any noticeable difference revving it at idle in park /neutral?

 

It could cause unmetered air to get past the sensor and make the engine run oddly and MAYBE cause the trans to shift weird. If that is the issue, it should go back to normal once you tighten the maf back down.

 

revs seem to hang for a split second and there is a vibration around 1300-1500 rpm after revving it up in park/neutral

 

If it really is the MAF causing that, which it could, it should go right back to normal after you tighten it back down.

 

If its loose/leaking it could be running lean....tighten it up and try it

 

If thats the case it should kick a P0171 'too lean' code Id think?

 

I would think he would get that code or something similar by now especially if he's been driving it like that for a while.

 

17K and a 21. Take it in.

 

no codes at all. might not be leaking enough yet.

 

to tighten a screw? the dealer will probably say "cannot replicate issue" anyway.

 

Did the truck act the same after you snugged up the screw?

 

I haven't remove the MAF on the Tacoma but all the MAF's I have changed have an o-ring sealing the sensor in the tube. There should be no leakage unless the o-ring has failed. Also the screw hole is usually a blind hole, so there shouldn't be leakage there either.

Also, if it was running rough and had an unmetered air leak, it would throw a code. Either a lean code or an MAF error code.

 

Possibly, depends on how much it was leaking. There is a threshold before a code will be set. A quick look at the LTFT would give you an idea.

I doubt that is what is causing the shift issues. But you never know.

 

You mentioned shifting funky. You paid for warranty. Plus MAF shouldn't come loose, and need cleaning at 17k.

 

I agree. It’s always better to let the dealership fix a problem under warranty.
Accidents happen, if an accident happens while YOU are fixing it. Well, good luck getting what you broke fixed.

After warranty expires, I’ll throw wrenches at it all day.

 

i'll let you know after work. haven't driven it yet.

 

it's not running any worse. it's still running in open loop a lot when i let off the throttle so I think it still has some learning to do. I need to do some highway driving and complete a few drive cycles before I know for sure. going to clean the MAF tomorrow too. also getting my bidirectional scan tool tomorrow (Anyscan A30M) so that should be fun to play with. Maybe i'll just reset all the learned values for transmission/fuel trims/throttle.

 

What is the truck relearning? Did you unhook the battery while checking the MAF?

If you have a scan tool and are monitoring data, Id think mass air flow rate and fuel trims would be good ones to look at. Obviously a leak would lead to lower MAF rates and higher fuel trims, though Im still not convinced thats your issue.

 

I agree. To me if the maf was the issue he would notice a big difference after tightening it up.