if i recall, the 96+ s/c cars have the warm idle rpm set at like 650. why do you think this is too low?
Are you getting a vibration or surging?
If so you should take a look at the trans and motor mounts and make certain there is no vac leak.
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1996 with 254k miles, L32 4" FWI -> ported N* -> Ported Gen V w/3.0" Pulley, Stage 3 Phenolic I/C, ZZP FMHE, 1.84 RR, Headers and 3" pipe to mufflers, F-body brakes, and lowered on Eibachs. -RIP
AMG C400 White on black. Stage 2 w/E30 - 11.9@117 -daily