UrS4

Hi gang.

Currently have a 91 octane tune from Brenspeed that was made when had the following mods.

SCT tuner with JLT II CAI, Steeda under drive pullies, axel backs

Have removed Steeda pullies and returned to stock pullies as car was having issues in 90+ degree weather on HPDE days.

Just put on jba cat 4ward shorties. Still have the SCT and JLT II CAI. Car does not throw codes but at times has a bouncy idle and has died at a stop if the ac is on. I increased the min revs to 800 but it still has issues from time to time. Reinstalling the tune doesn't affect it.

Do I need a new tune cause the pullies are different?

tx_zstang

No; the changes you did should not affect operational parameters enough to need a retune.
What issues were you having on warmer days? They're probably related to you idle issues.You may need to work with Brenspeed and get your tune corrected.

lawrencecar1

maybe just me but i would get a new tune with the shorty headers

JCON

Shorty headers alone do not need a tune.

Nuke

The majority of these type of idle issues are associated with fuel delivery. When was the last time you cleaned the TB and replaced the fuel filter? Do you run any fuel system cleaner (Techron, SeaFoam, etc) at any regular frequency?

Cleaning the TB, replacing the fuel filter and running at least one tank of the proper mix of SeaFoam would be my first plan of attack.

JCON

SeaFoam has kept my car running smooth but actually solved a lot of misfire and idle issues with a friends 2008 GTCS. I definitely recommend running it. Additionally, I try to stick to Shell, Sunoco, or Exxon/Mobil for gas. Due to their nationwide locations, most adhere to the strictest guidelines and are loaded with additional detergents that keep the insides of your engine cleaner than running cheaper local gas. In both cases, I still use SeaFoam every once in a while.

808muscle

Keeping the TB clean is huge. My car runs so much better when I clean it. The idle is so much smoother.