[a1handy]

I recently purchased an 04 Taurus with a 3.0 OHV engine. This car had not been started or driven in over a year due to a bad transmission. I started the car and it ran OK, replaced the transmission and again it ran OK for 50 or so miles. When starting it one morning it ran and idled rough, had spark knock and backfired through the intake and exhause. The codes indicate OX sensors were reading lean on one and rich on the other. Later I determined the gas had gone bad and turned to varnish so I cleaned the system and replaced the filter. The engine runs somewhat smoother but not much. I have several mechanics look at the car and all they can seem to tell me is that the OX censors are not reading correctly. Where can I go from here?

 

[Jeff K]

What were the exact codes? There are several codes associated with each of the 4 O2 sensors.

 

[Dubeckyj]

It might have fouled some plugs. Pull them out and see what they look like.

 

[a1handy]

codes were 2195, 6 and 7....I replaced the first bank of plugs and they were in terrible shape (probably never changed 139000 miles) but made only a slight improvement

 

[austex04]

Try checking out this thread, in addition to checking for other vac leaks http://www.taurusclub.com/forum/82-maintenance-repair/139394-just-purchased-gen-iv.html. They pretty much will all leak from that area when they age, I'm waiting for mine to start leaking, as I check mine every 6 months or so. You should also replace the plug wires, do a full tune up with a fuel filter as well. Once you get all the things done that will mess up o2 sensors, replace all 4 of them.

 

[a1handy]

Thanks, I had pulled a code for the IAC as well but the mechanic did not seem to worried about it. I will try what this thread suggests and post the results. The symptoms in the post you suggested are very similar to mine except mine may be more severe. I also notice slight improvement as my engine warms as well