Ok, the other day I changed the oil, air filter, and battery terminals. After that, the truck wouldn't crank. I tested the battery and found it was bad. So, I replaced the battery today and now the security light is on and the truck won't crank. What do I do?

 

Very odd. If the PATS system is active, it shuts off the fuel injectors, not the starter.

See if there are any codes in the ECM, and go from there.

 

After I took the key in and out a few times and flipped it over several times, it finally crunk up. Should I go get a new key?

 

Usually the key doesn't go bad. There is a silicon chip inside it with a very specific resistance. The PATS system sensor in the steering column reads it, and disables the PATS system when you have the right key in the ignition.

If you have any electronic devices near the key, that can mess with the system. I have seen simple things like those little grey electronic keycards mess with the system.

 

Update, I got it to crank. Thanks for the help.