I just installaed a ls2 gold blade 90mm. Ive been havin idle issues hard down shifts when slowing down and after driving if I rev the engine if it comes down its really slow from 3000 to 2000. My tuner isnt sure what the issue is. Any input would be great. Hptuners by the way.

 

Just on my phone this week, so no access to HPT, but check
that the throttle area is set correctly for the larger TB. Shouldn't
need any other changes in the tune for it to idle well. Should idle decent
even with no tune changes.

 

If i recall the LS3 90mm (gold butterfly blade) wont work due to it opening the reverse direction than the ls2 and ls1 style throttle bodies. But we can try changing the ETC Area Scalar from 5,060.2500 to 5,636.0000... Next time we meet up.

 

Need a idle relearn. If that don't fix it then the throttle body is bad.

 

You just need a tune.. Bring the raf down and increase throttle decay
Try lowering ignition timing a bit as well

 

change the TB size in the PCM