1999 21V TPS and IAC info

[Hooky]

I have a '99 21V with a Mercruiser MIE 350 MAG MPI SKI motor. Serial # 0L390068. I have a couple questions.
1. I have a loud hiss at idle, parts diagram doesn't show an IAC muffler, does anyone know if it has one and if so, is it the same part # as the slightly later models?
2. The mercruiser parts finder does not list part #s for the IAC motor or the TPS, does anyone know part #'s for these parts?
Thanks in advance!
Tim

[cltTige]

Go to marine engine .com and type in your serial. It has the throttle position sensor in the parts, under the intake section.
know mine doesn’t use the IAC mufflers and it’s a 98.