DJ's 02' Z28

iTrader: (2)

Lately I have noticed my car doesnt seem to be running as strong as it should. When I get in to the powerband it seems like im pulling a trailer behind me. I had the codes pulled today, they are as follows.....

P0131 Heated oxygen sensor - bank 1 sensor 1 (HO2S11) low voltage
P0141 heater condition (heated oxygen sensor-Bank 1 Sensor 2)
P0151 circuit condition (heated oxygen sensor bank 2 sensor 1)
P0157 circuit condition (Heated oxygen sensor bank 2 sensor 2)
P0300 cylinder misfire detected-random cylinders
P0332 knock sensor condition

I know the bank two sensors are for the cats. I have my cats gutted, they have been that way for about 4 years and i didnt have a problem with it untill now. my car has 131,000 miles on it and i have never had to change the O2's, fuel pump, fuel pressure regulator or fuel injectors. it seems to be running rich, and most time it doesnt start on the first try, weather it is hot or cold. ive also noticed that my oil seems to smell like gas, I think I may have a leaky injector. Ive noticed that for over a year now and it still seemed to run fine. Im wondering where i should start, could it be the fuel pressure regulator or should i start with new O2's? I changed the fuel filter not to long ago and it still seemed ok. I know that i probaly need to change all of them, im just a little pressed for cash right now, and not sure where to start.

Drew24

I would say clogged cat but you mentioned you gutted them. Do you have a tune on the car? Ill so think that your ecu could be acting up maybe taking a ****. The random misfires would not be related for the car to through o2 codes. what kind of mods that you have?

To check for that random mis fire code i would start by checking your plug wires for tears or burns. I have found the easiest way to check to see if its a plug wire would be turning off all the lights in the garage and looking to see if there is any arch from any wire. If that checks out i would be leaning more towards the ecu or bad tune. IMO

LS6427

iTrader: (2)

Pop the fuel rails off and check to see if a fuel injector is leaking. Turn the key to on and wait to see if one drips or squirts.

If not, then I would change both 02's.

Bad 02 sensor(s) will make you run rich, a leaky injector is the same.

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blade2222

change the O2's ,low voltage tells the PCM that it's running lean and it will enrich the mixture to the point of fouling out. I'd change them also just because they are old, they slow down with age.

LS6427

iTrader: (2)

Its just very wierd and a very slim chance that both 02 sensors go out at the same time...almost impossible.

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blade2222

mine did 1 week apart.

Drew24

the only time i have ever herd of them both going out at the same time is when my cousin put headers in his ls1 and they got heat soaked. He kept replacing them but he ended up having to wrap the headers and now no problem

LS6427

iTrader: (2)

Yup, its like a multi-engine plane. The PCM splits the two sides, they have nothing to do with each other.

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camaro981289

iTrader: (25)

I have the exact same problem minus the cylinder misfire code...my car is throwing the exact same codes as yours and is running crappy...mine has longtube headers with extension o2 harnesses and the rear o2s are simulators i dont have cats, my front o2s are connected into the bungees on the headers. Mine started acting up after i got caught in a bad rain storm

DJ's 02' Z28

iTrader: (2)

that was what I was thinking. Also the fact that most of the time it doesn't start the first time, that's why I was leaning to the fuel pressure regulator. The only mods I have are a FIPK and a loudmouth exhaust with the cats gutted. I also changed the plugs and wire out about 18000 miles ago.