Question about 1995 Cadillac DeVille
I replaced all the two O2 sensors a year ago, and I just replaced the catalytic converter in Oct of 2008, the plugs and wires are only a year old and I've replaced the PCV valve. Now I'm getting a check engine light with the trouble code P042 Left Oxygen Sensor Signal Lean. I use to get on average about 20mpg, not bad for a car with 435,000km on the original drivetrain. Now I'm lucky if I get 12mpg. I also had to change my oil again today as it smelled like raw fuel, the oil that was in it only had only about 20% use on it. I did not want to gas wash the engine so I just replaced it to be safe. Can this major change in fuel economy be caused by a small vacume leak or is just the O2 sensor has prematurally bit the dust due to its high mileage engine?
Any help or suggestions would be greatly appreciated.
You will see shorter service life of those O2 sensors with that kind of mileage. I would also suspect that the injectors are seriously worn if original. a few things to also look at that tend to throw 02 codes:
1: MAP OR MAS sensors,
2. worn timing chain
3: Restricted air intake (filter, or leak between MAS sensor and Intake)
4: Engine coolant thermostat (if the engine never warms fully, the mixture will be overly rich)
The O2 sensors tend to get wiped out by too much or too little fuel, too much in your case. you have to find the problem of fuel delivery or it will kill any O2 sensors you replace.
Have you performed a compression check? in some cases the piston, or rings have failed and allowed a large amount of fuel to enter the crankcase oil.
Posted on Jan 04, 2009
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
Tips for a great answer:
Apr 03, 2015 | 1999 Cadillac Seville STS
Mar 28, 2014 | 2007 Kia Rio 5 Sx M/T Hatchback
Jul 21, 2011 | Chevrolet Suburban 2500 Cars & Trucks
Jun 04, 2011 | 1998 Cadillac Seville
Jul 02, 2010 | 2003 Oldsmobile Alero
Apr 28, 2010 | 2004 Dodge Caravan
Mar 11, 2010 | 2004 Mazda RX-8
Nov 21, 2009 | 2001 Chevrolet Silverado 1500
Aug 14, 2009 | 2003 Toyota Corolla
276 people viewed this question
Usually answered in minutes!
Step 2: Please assign your manual to a product: