i have a 1993 camaro z28. sometimes it wont start and if it does it idles real low and breaks up in high rpm. but also sometimes it will run fine. what could it be?

 

Could be several things. How is the fuel pressure? How old is the coil, opti, and icm?

 

Have you scanned it for codes?

Courtesy of Shoebox:

http://shbox.com/1/dlc2.jpg

 

if there is no codes i would check these pretty much in this order

 

the coil, spark plugs, spark plug wires, fuel pump, fuel filter have just been replaced. i was thinking the opti but somedays it will run just fine without breaking up or idling low. and the only code i got was an o2 sensor.

 

Sounds like you got it all covered but the opti dude. If its the original, then its past its time.

 

What SPECIFIC O2 sensor code did you get?

 

i thought it was the opti from the begining. but didnt wana spend the money if i didnt have to cuz i have a 4 bolt 383 going in it. but thats down the road a lil after i buy heads. so ima replace it cuz it is original. i forget what the specific code was but it was #13 nd it was the left 02 sensor

 

[QUOTE=AN7967;5268444]so ima replace it cuz it is original.

Yeah, factory opti's time is up, even if it wasn't bad, its good preventative maintenance.

I would take care of that, swap sensors from left to right and see if the code follows. If it does, then replace the bad sensor.