I am SO going to cry. I've had enough with this car!!!!

Went to Emissions testing last week, and my 99 Taurus DOHC failed because the CEL was on through driving range. Came back with P0171, "lean on bank one." Replaced the HO2 sensors, went to one of those free scanning places (Auto Zone, Murray's, something like that) and had them reset the computer. The damn light came back on a day later. Anyone have any ideas about what to do now? I don't have the money to throw around on this, and Illinois is gonna suspend my license if I don't get this car to pass by December 20.

Aside, when testing the voltage on the O2 sensors, what setting should it be at? I have one of those voltometers, but it has about a billion different settings, and I'm not sure how to get an accurate reading.

 

Okay, well, still have a CEL on, and I've gotten some advice from a friend who recommends a vacuum test. I can hear air sucking right behind the throttle body, but the air intake is there, so I'm not sure if I'm hearing a leak or just normal air suction. Are there any specific sensors I should be looking at, beside the HO2s? One person said I may have blown the head gasket. Sounds extreme, since I don't see any oil, and my mileage isn't too terrible, about 250-280 miles per tank. Figure 14 gallons per tank, and I'm averaging 18-20 mpg.

Please, I haven't had any responses in a while, and I'm really looking for advice. I don't want to go to a shop, and have them take me for everything I got.

 

Heya's. Sorry I didn't see your original post. As you said, po171 is lean on bank 1. There's an entirely different code on the newer obd2 cars(yours included) which will differentiate an o2s problem and will point you directly to a slow functioning o2 sensor. PO171 code by itself means pretty much one thing only- Lean on bank one, meaning you have a vacuum leak. Also, in my exp, since it's only lean on bank 1, it leads me to believe that there's a leaking or disconnected vacuum hose at the back side of the intake manifold or throttle body. Take a good look at all the vacuum lines and hoses. Squeeze them. If they collapse easily or feel squishy or look cracked, replace the hose. PCV hoses do this alot since it's pulling in oil saturated air. Rubber pieces over time don't do well with oil. You can also get yourself a length of 3/8" hose and put one end up to your ear and the other down around where you hear hissing to help pinpoint where the vacuum leak is.

Good luck, and don't worry. I doubt this will turn into an expensive repair. Whoever told you head gasket is well... nevermind. )

 

Okay, well, I took it to a place that said we should change HO2s and MAF. We tried cleaning the MAF with electronic parts cleaner spray first, but that didn't seem to change anything. Almost $300 in now, and no change. My husband finally got under there and started poking around and found a HUGE hole through one of the vacuum lines. Bought some hosing, and changed it out. Cleared the code, gonna drive for a few days and see if it comes back on.

I have a question -- WHERE THE HELL IS THE PCV on this car? Is it on the back by the firewall, like I suspect? I can't reach it, and if it's really back there, how on earth am I supposed to get to it? I want to shake that !@$#%#$ and see if it rattles. If it doesn't, I'll be changing that too, just for posterity. Wish me luck.

And you're right about the bonehead who mentioned head gasket. I almost shot him myself. LOL

 

New issue with this car now --- I have a misfire on 2, and need to get to the rear spark plugs. What's the best way? Someone said go from top/passenger side, and feel your way around. Someone else said remove the plenum. And yet ANOTHER person said to go from underneath. So what's best? If I go from underneath, do I need to remove them one at a time, so I don't have to second guess firing order? If I remove the plenum, am I setting myself up for more problems?

Used to be, if I noticed a misfire, I could stop the car, shut it off, wait ten of 15 minutes, and it would clear itself.

The misifre seems to be worse with wet weather. I didn't have the problem over the winter, but anyone who lives in the Chicago area knows that yesterday (5-11-06) we had some FIERCE wet windy weather, and my car just hasn't recovered.

BTW, we found a HUGE hole ina vacuum line, so we solved that other problem.

Any advice quick like, please let me know. I have a half-day at work today, and plan to tackle this when I get home.