Filled up and Idling crazy

[PNWYukon]

We filled up last night and the Tahoe strarted idling crazy, almost died multiple times, the lights and dash were dimming in unison with the engine practically dying. This happened all the way home.

Has anyone else ever had this problem? Thanks

 

[SlowD]

Did you accidentally put E85 in?
The lights dimming is normal because your engine is dying out and the alt output voltage drops.
Just one of those things that will hard to diag on the Internet. Have someone test the output voltage of the alternator and check the battery to eliminate that all together.

 

[massivespl]

Get out your dmm and see if the alternator is working and putting out any power. Sounds like your alt is going bad.

 

[PNWYukon]

That would make more sense, but it was the same place we always fuel up. I will test the voltage with my Fluke and see if it is the alternator.

 

[SLCHOE]

Yep, unrelated. Charging system issues.

 

[PNWYukon]

Got ahold of the OBD2 and it gave me 3 codes. P0131, P0171 and P0300. Any thoughts?

 

[PNWYukon]

Put AcDelco Fuel treatment in the tank and believe it or not the check engine light went away! It is still idling rougher than normal at idle and dropping to around 500rpm at stop. So on we go to the next thing.

 

[PNWYukon]

Get out your dmm and see if the alternator is working and putting out any power. Sounds like your alt is going bad.

Alternator tested fine.

 

[nharkey85]

Still on the same tank of gas? Runs fine except for stopping and idling? How about fuel pressure issue? Plugs/wires good?

 

[PNWYukon]

Still on the same tank of gas? Runs fine except for stopping and idling? How about fuel pressure issue? Plugs/wires good?

Ran old gas down to 1/4 tank, added AcDelco Fuel Treatment, ran for a bit, then put in 12gallons on top. Ran good for a bit then rough idle at stops and turning. Then today the codes came a tumbling. 6 on the OBD2, but the same codes as before. Have not checked fuel pressure yet, have new plugs and wires, but the weather is shiii-tay!