FormulaTA96

iTrader: (2)

Well I've noticed for the past month or so that my engine has had a slight miss in it when accelerating,and I mean real slight,you wouldnt really notice it unless you were used to driving it all of the time..But last week I took it out for a drive and it started idling really rough and acceleration was horrible..I could floor it and it wouldnt get up and go at all,and it started backfiring a lot..Once I got it back home I gave it a few revs and I saw some white smoke accompanied with backfiring,so I was pretty sure I had an ignition problem on my hands..I plugged up my OBD reader and it gave me a code for bank 2 running lean and a bad crank position sensor..My crank position sensor cant be bad because my car still starts up and runs,so I'm guessing the opti going out and causing misfires is causing this code? The lean code I expected however due to having longtubes without cats and no tune..The problem at first would only arise once my engine would reach operating temp,but it seems now that it runs like crap as soon as I start it up,I dont have any problems with it starting though..I know there are tons of opti threads and I did some looking around and it seems that my symptoms match others that have had their opti go out,and Im pretty sure thats whats wrong,but I just wanted to get some opinions from you guys..Thanks.

FAD2BLK93

A lean condition can and does cause backfires. Are u able to read the datastream? I'm thinking the car is going into cloased loop, then goes lean from the signal of the o2. I would start with a scan, then 02. It does have some symtoms of the opti though.

Tbird232ci

iTrader: (4)

If you're getting a code for a crank position sensor, you should address that first.

I'm not completely sure about the LT1 cars, but if either the cam position or crank position sensors fail, it will go into limp mode, and read off of the functioning sensor to get you home.

SS RRR

iTrader: (2)

CPS will not influence engine operation. It is only there to detect misfires. Unplug your O2 sensors and see if your problems clear up. If they don't then you may have some ignition related issues going on. Perhaps a loose opti rotor. You do not need a tune with LT's other than to disable the rear O2 sensors.

FormulaTA96

iTrader: (2)

^ Hopefully thats where the problem lies,as that'll save me a lot of time and money..Thanks for the tips guys.

FormulaTA96

iTrader: (2)

Ok well I unplugged my 02's,and the wiring harness was covered in oil,thanks to my intake manifold leak..But anyways,after unplugging them I let the car run all the way to operating temp. and it ran just fine,my SES light even went away (wtf? you'd think unplugging them would keep it on) I then plugged them back up and let it run for a while and it actually kept running fine,but my SES light came on as soon as I started it up..So it seems the problem lies in the O2's??

SS RRR

iTrader: (2)

You need to get the codes to see what they are. Regardless whether your SES light is on or off the codes should be stored in the PCM. It would appear at least one of your O2's is fouled. How old are they?

FormulaTA96

iTrader: (2)

Well one I had put on when I had my LT's installed,which was only about 2,000mi. ago,so its pretty new..The other however is original lmao,theyd both be originals but one was ceased up in the manifolds..Guess I shouldnt have got cheap and only replaced one..I've also been getting really crappy gas mileage lately..

After plugging up the OBD reader again,the only code I'm getting is 0336 which is Crankshaft position sensor A circuit range/performance..Odd that I'm not getting the previous codes that said it was running lean and not even codes saying the secondary 02's are unplugged..