SkiBumDreams

I have been chasing problems all over my ignition since i bought this car a year and a half ago. recently it has been running very poorly thanks to big misfires. i got it scanned at advanced auto today came up with codes 64 (right o2 sensor lean), 97 (ign system prob 4x sensor circuit) and a couple i assume are form when i didnt have the alternator plugged in and ran out my battery codes 50 and 75 (low voltage) and code 99 (tach output circuit problem).

plugs and wires just replaced (already black i am sure), coil and icm replaced 2 months ago, opti replaced < 1 year ago

i have a lifter that is ticking that i need to dive in and replace but that really shoudlnt be causing this issue. btw what are the differences between stock lifters and the ls7 ones(not the caddy ones), if i use the ls7s will i need anything else besides the lifters themselves to use as replacements?

thanks, i did do a search for code 97 and couldnt find anything relevant on the first three pages.

Injuneer

Always use an LT1-specific code list, that would clarify DTC 97. Shoebox has a list:

http://shbox.com/1/Dtcs.htm

DTC 50 = System voltage low
DTC 64 = Bank 2 (right) Heated Oxygen Sensor (HO2S) Circuit (lean exhaust indicated)
DTC 75 = Transmission system voltage low
DTC 99 = Tach output circuit

DTC 97 = VSS output circuit

Indicates the vehicle speed sensor on the tranny ourput shaft housing is not providing the correct signal. Could be the sensor, could be the wires. Is your speedometer working? Have you disconnected the harness recently?

Appears you have a lot of stored codes related to the alternator disconnect. Why not clear the codes to get rid of those, then see what codes come back. Pull the "PCM BAT" fuse for 30 seconds to clear the codes.

DTC 64 can be the cause of the misfires, or misfires can be the cause of DTC 64. A scan would show you if the "lean" problem is unique to the passenger bank, or also close to setting on the driver's side as well. That would indicate whether the "lean" is due to something that affects both banks (low fuel pressure, faulty MAF readings, large vacuum leak), or something that is only affecting the passenger side (misfires, exhaust leak, faulty injector, faulty O2 sensor).

SkiBumDreams

Well neither i nor anyone i know has the hardware or software to do a scan. I am assuming (and that may be a mistake) that driver side is ok because all the plugs look fine after pulling them out where as all the passenger side plugs are black and "soot" covered. I did clear the codes when they scanned it at the store but the ses light wont come on again til after a few minutes of driving with it missing rediculously and by that time i was mostly home. i ordered the ls7 lifters and will be installing those when the get here. i needed to replace them whether they are the root cause or not. I am just hoping that this doesnt lead me to yet another opti replacement.

Is it possible that the vss circuit fault was triggered by the disconnected alternator? I havent had any speedo issues and since when the battery was draining the speedo acted up along with the tach, seems logical to me.

Thanks for your help