Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

04 Ford Taurus Running Terrible


I have a 04 Ford Taurus and it just started running very rough. It sputters and vibrates and is not running good at all. I was driving and everything was fine and then all of the sudden it starting running very poorly. It makes a clicking noise while running and and basically barely sputters at idle. I stopped driving it because literally barely runs and now looking for help.

I hooked a OBD11 on the computer and the following codes came up.



It looks like the top 3 are cylinders that are running lean.

And the bottom two are misfire codes. It also says something online about o2 sensors.

I’ve read online it could be a vacuum leak. What are some areas to check and could it be something else?

Please help

Thanks everyone!

P0171 and 174 are lean running fuel codes bank 1 and 2, P0175 is rich running code.

The P2196 and P2198 are downstream O2 sensors running rich.

The codes contradict one another. It can’t be both rich and lean at the same time and none of the 5 are mis-fire codes.

Go here and read what the causes of each of the 5 codes that are being thrown. Find a common fault for ALL 5 and start there. Hint: Dirty or faulty MAF sensor is in all 5. I suspect that is the problem.

I just ran the OBD 11 again and I’m getting the same codes above and also P0340.

It looks like that is a Camshaft position sensor failure. Would this be the cause now that that one has appeared?

I actually another ford Taurus with the same engine I can use as a parts car. Most of the parts are still good from this one. I can swap out the MAF sensor to see if it is that. Would there be any other things to check?

As I said before… look for the common cause of ALL the problems (codes) being set. If I add the P0340 to the list this is the only thing common across all the codes.

the PCM may have failed

Read more at:

Step 1) Clean the MAF, test the car. Still runs bad?? Unplug the MAF and see how it runs? Kinda OK? Swap the MAF or buy a new one. Still bad?? Probably the PCM.

Have someone check the fuel pressure.

It’s a little complicated on your vehicle.


If you feel lucky, try replacing the pcv valve if your car uses that part. Also look for a cracked rubber boot in the throttle body intake area.