My car always seems to idle a little rough. It is something that I notice and it bothers me. My car has 60k on it. Perhaps the IAC needs replacing? I have done every kind of preventative maint possible except that. Or maybe it is just normal for the V-8 to idle slightly rough?
Mod motors idle waaaay smoother than pushrod's... I had the same problem and as it got worse I started with replaceing the alternator, coil packs, wires and plugs...that didn't fix it so I pulled the codes, and showed to have a bad front O2...replaced that, but it made no change...so I blew the dust off the Haynes and tested the TPS, IAC, MAF etc... and narrowed it down to the MAF...so I unplugged it... and low-n-behold the engine idled smoother without the MAF...SO, I bought a new MAF straight from Ford($216.00 after core but only $106 with my hook-up ) and that finally fixed it. This particular car has 15X,XXX on it, but I know I don't have to tell you that MAF's are sensitive and cannot be trusted to last any guaranteed length of time. Anyways, good luck!