i have a 99 sierra with a 5.3 ive got the stock fuel injectors in it. would i gain any power by going with the injectors off of a 02 5.3. will i have to get a tune before i put the injectors in?

 

ttt. id like to know this as well.

 

The injectors will plug right in, but the PCM really should be tuned to accomodate the increased flow rate of the 24lb 02 injectors (99's are 21.7 or something like that). Without having the PCM tuned, the engine may actually run richer since the PCM has the 99 injectors duty-cycling more.

FWIW, I swapped injectors about a month or so prior to having my PCM tuned will no ill effect.