pdub42

So yesterday I am driving on the highway and I am getting low on gas, like 1 mile left before I find a gas station. I finally find a sunoco with 93. When I hit 93 on the pump it acted weird and all the button lights when out but the 93 price showed up so I didn't think anything of it. I put a half tank in and drive the rest of the way home (10miles). The car started to idle a little rough on the way home and I almost stalled it at a light because it was idling so weird. I then get home shut off the car and leave a little later with the car shaking pretty bad at idle and a I get a CEL P0171 system too lean (b1). I shut off the car and think maybe the pump screwed up and gave me a lower octane gas and the tune was screwing up so I retune the car with the 87 street tune. Start the car it idles 2 seconds and dies. I tried a few more times and the car would only run when giving it gas to keep the rpms up. I retuned back to the 93 performance tune that would at least run before and it now does the same thing. I know this resets the KAM when downloading a tune but I am not sure what the problem is. I have never had a problem with this car before and it started right after I put this gas in my car so I am wondering if it is something with the gas? Anyone had something similar and know what to do? Any way to check the gas and see if it is ok?

kevinmalec

Since your car was fine before getting gas, my assumption is the gas is bad.
Another source could be a clogged fuel filter and/or issues with the fuel pump.
Maybe try putting some Chevron Techron fuel system cleaner or seafoam in the tank and see if that helps.

moosestang

p0171 is bank 1 lean. do you have aftermarket COP's? Even if you don't it could be a stock cop going bad. I'd switch the cop's to the opposite side and clear the codes. If it throws a p0174, then you know you have a bad coil. Bank 1 is the passenger side.

pdub42

I am running the stock COP's, I was thinking maybe an o2 sensor went bad but just thought it was wierd with the timing, I will try switching the coils though and see if it changes codes if I can keep it running long enough.

moosestang

02 sensor almost never fail. Lean doesn't always mean it's not getting enough fuel either. You can get a lean code if 1 or more cylinders aren't firing causing extra oxygen in the exhaust.

The easiest thing to rule out is the coil on plugs.

solaratomic

Fuel filters are cheap, I'd try that before anything else. It's on the bottom of the car under a plastic cover, right up under the front of the driver's door. You may have stirred up trash in the tank that got sucked into the fuel filter and clogged it. Espically if it's never been changed. Good Luck

aero86

lean codes usually indicate some sort of vacuum leak if the o2's arent damaged. they usually dont go bad, as already stated, except for the heater circuit. you might look for a vacuum leak, other than that, its hard to tell without seeing it. but, seeing how you filled up on an empty tank, you could have stirred up crap in the tank, as has been stated. or bad gas. just seconding these statements

Simon1

I wouldn't change anything until you rule out the fuel.

Gary Ugarek

I try to never let my tank get below 2 gallons. The amount of crap that falls into the gas station underground tanks would amaze you. While the tankers seal up the tanks well, the moron checking the next morning sometimes doesn't throw the cap back on and with elements such as rain, snow, and overall crap and debris it is a wonder how they even manage to not kill more cars off.

moosestang

clogged fuel filter should affect both banks, same for a vacuum leak or watered down gas, unless it just happens to be one of the bank 1 intake manifold gaskets.