Code on my 99 with a 3.8 says it's the crank position sensor. I replaced it to no avail. Service department told me the vehicle computer needs to be flashed. Is this correct? It turns over but will not start.

No injector pulse.. Water in gas... Plugged exhaust.... Engine try to run on carb cleaner sprayed into throttle body?

I'll have to check on those. I rented a code reader at Autozone and that was the only code it gave me. I can unbolt the cat and see if it starts. No water in the gas. How would I check the injector pulse?