Truck is throwing that damn P0101 code!! (SOLVED)

Ok guys,,, this must be the reason.

My gas cap. Three months ago getting gas my light came on and i tried my cap and it went off.

Since I’ve replaced the cap. But my light came on again.. after it being on over a few shorter trips I got gasoline and it went off instantly.

So what to do ?? I’ve already changed caps. Is there a vent on the other end??

Thanks

 

Hello again,,

If I have a new cap I’m guessing it probably works,,, venting properly. Sealing correctly.

Gonna give it credit as ok.

After driving on a full tank without the light being on,, it comes on. The light came on and stayed on until with about a 1/4 tank I invested in more gas and the light was instantly out. My gas tank issue is creating this sensor problem.

Drive a quarter tank out and light comes on. Stays on over a number of days during several trips until the next gas purchase / cap removal. Take this Cap off and back on its an instant fix.

I imagine the issue could be the air pressure in the gas tank including the fuel line up to the motor. As if the more gas used is creating a loss of volume creating a negative pressure inside the tank (?),, cause it’s not equalizing with the outside and sending a signal of a different airflow than the sensor is looking for. Or the gasoline flow itself is slowed by the tank not venting.

How is my fuel cap controlling that light being on or off?

The truck continues running well and the same with light on or off.

Is there a vent on the tank besides the gas cap?
If no other equalizing facet does that mean my gas cap vent is blocked?

If there is another tank vent, which is clogged,, could that situation change the “air dynamics” inside the tank?
And in turn cause a wrong air flow pressure,, sending a bad mass air flow reading? Could it affect fuel flow? How does fuel flow affect this sensor?

Here’s my puzzle...
If the gas cap is working properly and the light is off but then my light comes on what is the thing affecting air flow for whatever desired criteria the sensor looks for. What on this gas tank can be affecting the air pressure?

What can go on inside the tank ?
What can cause the tank to not regulate itself? To change in a manner that makes this light come on? More air or less air, whichever. If nothing why the light? And then,,, Release air pressure or neg pressure(?) by removing the cap and everything is ok. Correct Air flow is now restored turning my light off. Could the different values taken wherever around the tank ,, due to my imaginary gas tank vent being plugged be sending the wrong info?

I have a half tank of gas. I’m gonna run it out. If my light comes on Again I’ll remove cap and reinstall. And see if the engine light is on or off And report here.
If light doesn’t come on fill er up and keep driving til it does turn on again. And that'll tell me nothing more than I know now.

Shit , I don’t know.

Help

 

Hello all,, I’m needing a knowledgeable soul to trouble shoot why my gas cap is causing my check engine light to show a code of P0101 .

This has gone on 4 months . I bought a new gas cap a month ago but the light came on again for 75 miles ,,I thought it must be something else until I released the cap and tightened it again. Light went off before I could look.

Are you the mechanic to solve this? Can you sort out why the gas cap is causing the mass air flow sensor to show bad.

How is the cap affecting air flow? Thereby the sensor is signaling the check engine code.

Truck continues running nice. Light on or off.
Thank you

 

Old thread, I know, but worth a try. I have a similar issue with P0101. I comes on after driving for 2-3 hours, normally after I filled it up and do a hard accleratation. Overtaking or going up a hill. Runs fine though, from what I can tell. The CE light is on for a few days then it dissapears.
@08toy, did you ever find a solution?

Thanks