View Single Post
  #4  
Old 03-04-2017, 08:30 PM
davet753's Avatar
davet753 davet753 is offline
David Thomas
 
Join Date: Mar 2013
Location: Knoxville, TN
Posts: 443
I had that issue with an 03 Buick LeSabre (same engine). I traded my Town Car in on it, and the light came on before I got the Buick home. I replaced both oxygen sensors myself (only took about 30 minutes). The front one came right out, and the rear one was much harder to get to turn, but I got them. I ordered them online, and the cost was about $25 each.

Reset the codes, and a day or two later the service engine soon light was back on (same code). I had the catalytic converters replaced (about $450) and drove it for a week or so before the light was back on. The mechanic found a small intake leak (very common on 3.8 engines) that he said was causing the problem. $500 later and another weeks worth of driving, and the service engine soon light was back on.

Took it to another mechanic, who drove it around for a couple days trying to find the problem. He gave up and referred me to a GM certified mechanic. He changed the spark plugs, and the light was back on in a day or so.

During the entire time, the car ran smoothly, and got great gas mileage...it was just that silly service engine soon light stayed on. I had to replace about a half dozen dash lights (the little ones that come on at night), and if I had it to do over, I'd have removed the service engine bulb. I drove it for a couple more years before trading it and going back to a Lincoln.

If you want to change the oxygen sensors, I'd recommend doing it yourself or taking it to another mechanic. There's no sense replacing the converters unless you have to.