I have looked for a Diablo tuner for my 98 Z28 and it looks like they don't make one for that year. Is that true?

 

It's true. If all you want is a handheld, Vinci/Crane just released one for the '98's.

 

IMO, the handheld tuners state they are for a specific year of the car...I think it's BS. It's the same engine, same ECU, etc. Summit was selling each tuner for a specific year, but another company was selling one for all years. I recently untuned my Hypertech because my car is running a little ghetto until further notice. I'm going to try and install it on my Dad's '04 Vette and we'll see if it works!

 

if you knew about the 1998's then you would know that the ecu is completely different than the 99-02, which is why it does not work.

The hardware is the same, but the software put on the 99-03 ecu's are different. 2004 goes to a 1mb flash, vs the 512K that the 99-03 ls1 ecu;s use so good luck with that

Ryan