Multiple OBD codes

[Tiggetty]

So i'm failing emissions tests because of three codes.

My car is a 1999 Oldsmobile Intrigue 3.5

p0304 is cylinder 4 misfiring. Does anyone know how the cylinders are numbered in a 99 intrigue 3.5 engine? I thought odd numbers were on one side and even on another so i took off the front side coil pack thingy and pulled the center plug (assuming it was either cylinder 3 or 4). Replaced the spark plug but ultimately pulled the other two and cleaned the housing and plugs because they were completely soaked and filled with oil. I'm assuming this means i need to replace some rings? Misfire didn't go away so tomorrow i'll do the other side.

p0141 is Oxygen sensor bank 1 sensor 2. Has anyone replaced this themselves that could throw out some input on how easy it is to do yourself as opposed to a shop. From what i can dig up that specific O2 sensor is the one right before the catalytic converter but i'm not sure. Autozone is gonna hit me for 70 bucks for a new one so i can't imagine what my mechanic will charge.

p0442 Is a small leak in the Evaporation system. The most common cause is a faulty gas cap. The gas cap has been replaced and still the code pops up. Does anyone have any probable causes or dealt with this in the past?

Thanks in advance for any help!

[Ruley73]

Originally Posted by Tiggetty

So i'm failing emissions tests because of three codes.

My car is a 1999 Oldsmobile Intrigue 3.5

p0304 is cylinder 4 misfiring. Does anyone know how the cylinders are numbered in a 99 intrigue 3.5 engine? I thought odd numbers were on one side and even on another so i took off the front side coil pack thingy and pulled the center plug (assuming it was either cylinder 3 or 4). Replaced the spark plug but ultimately pulled the other two and cleaned the housing and plugs because they were completely soaked and filled with oil. I'm assuming this means i need to replace some rings? Misfire didn't go away so tomorrow i'll do the other side.

The oil is likely from the spark plug tube seals leaking. This happens quite often on DOHC engines. What spark plugs are in it? Regardless of what anyone else says, ONLY use NGK PTR5C-13 (stock #7730) or AC-Delco 41-980 (which are the NGKs in an AC-Delco box). Any other plug will give you driveability issues, subpar fuel economy, and/or wear out prematurely. Also check the condition of the plug-to-coil boots. Sometimes they become brittle and crack causing a misfire. The ignition coils rarely fail on these cars so your misfire is most likely due to the plugs or boots.

The firing order is (from passenger side to driver side) 2-4-6 on the radiator side and 1-3-5 on the firewall side.

Originally Posted by Tiggetty

p0141 is Oxygen sensor bank 1 sensor 2. Has anyone replaced this themselves that could throw out some input on how easy it is to do yourself as opposed to a shop. From what i can dig up that specific O2 sensor is the one right before the catalytic converter but i'm not sure. Autozone is gonna hit me for 70 bucks for a new one so i can't imagine what my mechanic will charge.

The Bank 1 Sensor 2 sensor is actually the downstream one located behind the cat. It is installed on top of the exhaust pipe pointing down and is very difficult (but not impossible) to replace without partially dropping the exhaust pipe.

Originally Posted by Tiggetty

p0442 Is a small leak in the Evaporation system. The most common cause is a faulty gas cap. The gas cap has been replaced and still the code pops up. Does anyone have any probable causes or dealt with this in the past?

Actually, in my experience I've found that a plugged air filter, loose air intake clamp or a vacuum hose leak usually cause the P0442 code. A loose/bad fuel cap usually causes a P0440 on GM cars.

Good Luck