I just filled up with gas 4.2 miles ago. I just left home to go to watch a T-wolves game at my buddies house and all the sudden the car starts to stumble and tries to die. This happened as abruptly as flipping a switch.

I tried swapping out the O2 with an old one I had (replaced due to gas mileage but didn't help much). I do get an error cods of "171 fuel trim lean". Is there something mechanically that broke or mybe the new gas is hitting the engine and it doesn't like it?

I can get video of the problem if it helps.

MAF sensor?

I do have my scanning software for my laptop so if anyone has readings I can take, let me know. I do believe the MAF was adjusting with the idle, but don't remeber what to what.

A bad MAF can send your car into crazyness. You don't really have much else on there electronics wise that could send it into death mode like that though, so i'm leaning for that, otherwise check all vaccuum hoses, especially the big one that goes to the firewall, if that'* off, you'll have a hell of a time driving it.

I think the o2, and IAT, wont do this when they go south, but the MAF is one of the big ones. Another being the knock sensors, but i doubt you're getting enough knock to kill it by timing...

I showed 55 (i think) for total knocks after running it for a few minutes while reving the gas.

I'll go check the hoses.

I'm thinking maybe bad gas, bad driver, or the fact that it is due to blow up soon anyhow since it is paid off, ( Some know the story , LOL)


Was it empty when you filled it up? I know that some stations do not check and don't' care how much water is in their tanks so when it gets close to empty you start to get water in your gas. But I can see why you thought it was your O2 sensor though with a lean code.

Considering the milage on the new tank (4.2 miles) and the fact it is a new full tank, I can see how gas may be the issue. If it is the issue, how do I go about fixing it?

Well if it is bad gas then you would have to drain it somehow then get some good stuff in there. NOW to help get moisture out of the tank you can always put in some gas line antifreeze ( kinda hard to find this time of year) since that is what it does displaces moisture.

Well, I put in a bottle and a half of STP stuff (made for removing water, improving performance, etc...) last night. I put it in a bit on the heavy side (enough for 20-25 gallons). I have been home now today for 30 minutes running the car and the idle has smoothed out some. It still isn't idleing like it was but it does seem to be smoother (less attempts to stall). I'm gonn alet the car sit there and run as long as I can tonight to let the gas get burned off some and get the STP entirely thru the system.

If this makes it better I might drain the gas and get 5 gallons of new gas (different station of coarse) and see how that goes. I still get an engine light, that I haven't scanned yet but I can guess what it is (same as before).

Ironically, I was thinking the last few days "Hrm, my car hasn't had any major issues in a looong time...". Dammit, I jinx'd myself.

Where'd the bad gas come from?

Beans? Burritos? (sorry i had to lol)