Have you looked at our exhaust flap? I don't have one, but I hear they rust closed...and there's some famous mod with a golf tee that I haven't heard about in a while...probably for a good reason! But, have 3 of 4 02 sensors with signal to ground problem seems odd...I wonder if it's because half your exhaust is closed...and maybe doesn't open up?
Worth a peak up them.
dmax on the radio--answering all your car questions as best I can!
watsonnwatson.com every Wednesday at 9 p.m. NYC time. Call in! (661) 449-9340 Click "Watch and Chat"
Please 'friend' me!