hi im new to this site from iowa and like the title says i have a 97 trans am with the lt1 with 110k on the clock and lately has had this code.. so ive replaced the plugs, wires, opti cap and rotor, icm, coil, fuel pump, fuel filter, intake gaskets, and a fuel injector rail that was rebuilt with all new parts and it still runs rough when it gets warmed up and the ses light flashes and stays soild and repeats and the only code i get is the p 0300 random cylinder misfire code and don't no what to do any ideas would be a great help...

 

Have you checked the valve adjustment? Have you done a compression/leakdown test?

 

i havent checked the compression yet. but i did check the rockers and they are all where they should be.

 

Since the problem occurs when it's warmed up, try disconnecting either one of the front O2's and see how it runs then. If it's better, you have a closed loop control issue.

If not, let us know.

 

both o2 sensors in the front are new this spring when i put the long tubes on the car..

 

That's good that you changed them but I don't care that they are new. I wanted to know if when you have one disconnected and it forces the PCM into open loop, if it runs better.

It would be helpful to know since you seem to have a problem after warm up and appear to have changed nearly everything in sight.

FWIW, many have damaged their O2s by putting them in their headers BEFORE they ran it to burn out harmful byproducts.

Control problems while in closed loop is not just from O2s. I found my wiring problem by doing it.

 

i drove it today with the left side front o2 sensor unpluged and it made no change in the way it runs..

 

Opti cap and rotor...that's less than half the problem. There are alot more things to go bad in an opti.
Are you getting a hi res signal and lo res signal from the opti.
I believe a failing opti can cause your problems and never throw codes.

 

whats the best way to test the signals, also if thats the issue whats the best replacement opti to use so i dont have to rip it all apart again in a few months