This is the only code I can get to come up when checking. Here are my problems.

-Car only starts after sitting for extended period of time.
-First initial start up after it has been sitting the car will remain running for the amount of time it takes the temp to reach near 200-210 or so then it dies.
-Took ICM into advance to have it checked, cold and hot(immediately after car died) and it passed.
-Checked coil with meter and it's fine.
-Tested alternator and it's fine.
-Fuel pump seems to run for excessive amount of time to prime.
-After sitting for almost 2 hours last night in a walmart parking lot I got it to fire up and didn't need the tow truck which just pulled up, however 5 minutes down the road the car died while cruising.
-I've checked for bad wires, burnt wires, bad harness spots and pigtails...found nothing.
-When the car does start and I'm able to run it for a few it seems fine, even the 5 minutes the other night it was running just fine before random shut down.
-Checked wires, see no arcing.

This problem started yesterday evening, no symptoms or trouble before now. I don't know where else to lean besides the opti as it pertains to this code. I am going to check fuel pressure though and rule it out. Any ideas?

 

According to the FSM, DTC 18 is a problem with the fuel injector circuitry and does not refer to low res failure as you indicated.

Ignore This Post !!!!!!!

 

Ahem....Code 16....cough!!

 

Whoops!
DTC 16.
The low res pulse (pulsing ground) is generated by the opti and sent to the PCM. If the PCM does not see the signal it will disable the fuel pump and fuel injectors. Look for a wiring problem between the opti "A" terminal (red/black wire) and the PCM B2 terminal ("B" connector, pin #2). If the wiring is OK, then the opti is probably bad.
The PCM applies 5 Volt to the B2 terminal, the opti applies a pulsing ground to the other end of the wire and draws the 5 Volt down to near zero, the PCM recognizes this as a low res pulse.

 

^ Makes much more sense when you clean your glasses, eh? lol

 

Try a new Opti harness. They're not too expensive and buy two if you can just so you have it. Only other thing I can think of is the Opti itself....

 

I don't want to fudge with this opticrap anymore :/ booooo! I'll dive in and take a look. Thanks.

 

Make sure the connector from the PCM to the opti harness is good and tight as well (connector on passenger side of intake manifold). Mine had bad contacts on the PCM side of the connector causing intermittent shutoffs, backfiring, sputtering, dying, etc. I took a small screwdriver and lifted up all the contact points to ensure it was making good contact with the pins on the opti side of the connector.