those idle numbers look ok to me, remember the tachometer isnt super accurate.
like people said before many things could cause a rough idle/stall, my 88 never stalled, except when the crank sensor did fail, then it had to be towed home. and when the guy at midas didnt disconnect my batt before welding, he fried my ignition control modual, and that gave me a rough idle.
loose connector on crank and camshaft sensor
bad plug wires
ignition control modual (thing under the 3 coils)
engine ground cable
fuel pressure reg
go for the cheap things first.
1999-2007: ___1988 Bonneville LE LN3 (Vin C) @ 273,000 miles
and still going strong (<-Faded sun fried grayish ie needs paint)
2007-Present: ___1993 Bonneville SE L27 @ 210,000
Speeding around So Cal (<-Beautiful Forest Green)
Mods: Sylvania Silver Star headlamps. Remote start system with pageing device. K&N air filter. Tranny Cooler. High-flow cat with Magnaflow muffler. Full Class II hitch setup.