Originally posted by marketplace_man:

I have a 98 contour 2.5 l.I just got the codes read,they are 153,401,1131,1171 and 174.The car runs well enough but is hard on fuel.Dealer told me it was a bad mass sensor so I repaired it.No change.Next it was the back side catalytic,now both upper O2 sensors.Anybody got any ideas?




P0153 O2 Circuit Slow Response (Bank 2, Sensor 1) *
P0401 Exhaust Gas Recirculation Flow Insufficient Detected *
P1131 Lack Of HO2S11 Switches - Sensor Indicates Lean (see P2195) *
P0171 System Too Lean (Bank 1) (there is no 1171)
P0174 System Too Lean (Bank 2)


My suggestions:

Replace both upper O2 sensors (P0153 and P1131)
Perform TB cleaning (EGR ports) (P0401)
Replace UIM and LIM gaskets plus PCV valve (P0171 & P0174)(Check for other vacuum leaks, also)

It is the normal recommendation to address the first code received first. Upon the repair of that code, continued testing is recommended to progress to the next issue.

Loading up the shotgun and doing everything at once will most likely fix everything, however, this tactic may cause higher repair costs. If this were my car and I were doing the service myself for only parts cost and my time, I would personally go the shotgun route. If you are paying someone to do the work, you should consider carefully the costs involved. Total parts cost for the above procedures is only around $160-170.

Steve

98 Contour SE Sport 2.5 Duratec ATX The wifey's car 89 Taurus SHO - 246K miles 94 SHO ATX - 190K 1997 F-150 5.4L ATX - The Workhorse 150K. ANY THREAD WITH "OMG" or "WTF" ETC IN THE TITLE WILL BE IGNORED!