Ford Repair: Ford/Taurus-2002 SES/3.5 L engine/65,000 miles, ford taurus, definitive causes

Question
Do you have any suggestions on what types of things should be looked at?  Other than spark plugs and wires?  My son (21) is going to replace these for me and wanted to give him some other hints as to what could be the cause.

Thank you!

Mary


-------------------------
Followup To
Question -
I am having a prob w/my ford taurus SES, 2002 65,000 miles (mostly highway).  It has a 3.5 L engine.  My check eng light came on and it hesitates/sputters while driving.  So took it in and they said it was a sensor managing the back exhaust.  Changed the sensor, re-set my eng light and not even 24 hrs later, it came back on.  They were wrong as it still does the smae thing. Took it back they came up w/codes PO305 and PO 306 so now they say change spark plugs and wires.  When I asked if the light would come back on tomorrow?  THey said "well of course, after all, you have 65,000 mi on your car!"  Dont feel very comfortable with their guess work thus far.  My car isn't quite "over the hill" so I need to fix this problem.  Any ideas on what could cause the problems?  Any help very much appreciated.
Answer -
Mary-

  Well...the codes they pulled indicate that you've got a misfire in cylinders 5 and 6.  Now that could be caused by a number of things, but if I were you I wouldn't even bother with the shop you've been taking the car to.  If their response to a problem is that you car has 65K miles (which is actually relatively low), then I'd run as fast as you can to another shop that will give you definitive causes in a language you can understand.  Guess work is not a good way to conduct yourself as a mechanic and while their suggestions on replacing the plugs and wires may be correct, I wouldn't feel comfortable with them having my car either.  Once it's fixed right, the light won't come on anymore.  Hope this helps.

Steve

Answer
Mary-

  I honestly wish I could give you something more definitive to look for, but those trouble codes are so vague that it's hard to come up with a proper diagnosis.  They could be caused by the exhaust oxygen sensors you mentioned (otherwise known as "O2 sensors") or a large host of other problems.  I would start with the plugs and wires since they're an easy fix.  make sure to check the plugs for black soot because if the engine is running rich (too much fuel) like it should with bad O2 sensors then that may be your problem right there.  If they look ok I'd still recommend having a reliable shop have a look at the car.  With those codes alone it's hard to put my finger on one specific problem.

Steve