keenyoung

I have a 1999 Cougar 2.5 that is throwing codes P0174 and P0175. Bank 2 running too lean and bank 2 running too rich. It also shows P0301, P0302, and P0303, misfire on cylinders 1,2,3.

So, it's running rich and lean on bank 2, and misfiring on bank 1.

The car runs fine about 75% of the time. Sometimes the idle gets pretty rough, mostly when in park. Sometimes it runs rough at idle in gear. Lately, it sometimes runs rough at 30-35 mph. Sometimes when in cruise at 60 mph it jerks and hunts for proper speed. Today after idle for 3-4 minutes at the drive thru, it blew out a cloud of smoke and ran really rough until I got it up to 30 mph.

Any thoughts?
Thanks.

R.S.LOGAN

First thing I would check would be plugs and leads , check / clean MAF sensor and check for any vac . leaks from hoses .

keenyoung

Ok, I did the things you suggested, thanks. Plugs/wires look good. MAF clean. No vacuum leaks found.

After some more diagnosis I replaced the PVC valve (oil in the throttle body), and the DPFE sensor. I reset the ECU, and ran it thru a couple warmup cycles. Now all the original OBD codes are gone, but now it's giving me a P1131 O2 sensor detects lean.

The car runs great cold, but when warm it idles badly in gear, and dies when put into park. It has plenty of power at higher RPM, but occasionally coughs at constant throttle.

So what now? Throw $65 at an O2 sensor? Or throw $100 at a repair shop to find the stinking vacuum leak that must be there somewhere?

R.S.LOGAN

Possible causes ,


H40 DTCs P1131, P1132, P1151 AND P1152: UPSTREAM HO2S NOT SWITCHING. DTC P1130: FUEL SYSTEM NOT SWITCHING AT FUEL TRIM (RICH OR LEAN)
Diagnostic Trouble Codes (DTCs) P1131 bank 1 (Cylinder 1) and P1151 bank 2 indicate the fuel/air ratio is correcting rich for an overly lean condition. The HO2S voltage is less than 0.45 volt. DTCs P1132 bank 1 (Cylinder 1) and P1152 bank 2 indicate the fuel/air ratio is correcting lean for an overly rich condition. The HO2S voltage is greater than 0.45 volt.
DTC P1130 and P1150 indicate the fuel control system has reached maximum compensation for a lean or rich condition and the HO2S is not switching.
DTC/HO2S Reference List
•HO2S-11 = DTCs P1131, P1132 and P1130
•HO2S-21 = DTCs P1151, P1152 and P1150
Possible causes:
Fuel system
•Excessive fuel pressure.
•Leaking fuel injector(s).
•Leaking fuel pressure regulator.
•Low fuel pressure or running out of fuel.
•Contaminated fuel injector(s)
•Vapor recovery system
Induction system
•Air leaks after the MAF.
•Vacuum leaks (vacuum lines and gaskets).
•Restricted air inlet.
•PCV system.
•Improperly seated engine oil dipstick.
EGR System
•Leaking gasket.
•Stuck open EGR valve.
•Leaking diaphragm.
Base engine
•Oil overfill.
•Cam timing.
•Cylinder compression.
•Exhaust leaks before or near the HO2Ss.
•Check intake air system for leaks, obstructions and damage.
•Check air cleaner element, air cleaner housing for blockage.
•Verify integrity of the PCV system.
•Check for vacuum leaks.

Cody7

My cougar was doing that a whole back and I cleaned the maf sensor changed plugs and wires and it went away make sure to check the car for it being clogged because of it running Rich on one side I as well changed my cat an o2 sensor and had my throttle body cleaned good luck

Cody7

Also an exhaust leak will/can cause a o2 sensor to not read or give faulty readings I had a o2 sensor that was "dead" and fixed my exhaust leaks and it comes into spec. Hook it to a scanner and watch the o2 sensors