Truck started not only hard, but funny,(like having to crack 3 injector lines),but would'nt catch after lines were closed. Checked codes,P0602 came up,cleared,no problem since.What could have caused this?:banghead:

Using any programmers? (Smarty or SuperChips) Try returning to stock...

The 602 is sometimes called the smarty code.It's fine if you have a smarty i get that too.

Yeah the reason behing the P0602 code is the fact the fueling map is altered and the ECM checks the fueling table and it doesn't match the stock checksum. At least what I've been told...