Lexus Repair: Timing Belt, changing spark plugs, jiffy lube

Question
I'm by nature a do-it-yourselfer.  I've done everything from changing spark plugs to changing clutches and even entire transmissions on other cars -- But I'm a little nervous about working on my '93 SC400.  Is there anything special that I need to know about changing the timing belt on one of these cars?  How much stuff do i need to take off before I can get to it?  I know that the water pump is reccommended to be changed at the same time, but is there anything else that should be changed at the same time.

I bought this car about a little over a year ago, with 120K, it's now up to about 180K.  Before I bought it, the guy said that the timing belt had just been changed, but I believe he lied to me - when I had the oil changed at my local jiffy lube, they told me that they saw evidence that the timing belt needed to be replaced.

It's begun to hesitate a little, particularly in the lower rpm range, and I'm not sure why.  I changed the spark plugs, fuel filter and air filter when it first started, but it seems to have gotten a little worse since then.  I'm thinking that the timing belt could resolve this.  Any other reccomendations you could give me on that or just general maintance for a car that's gotten 50K miles in the past year would be helpful.

Thanks a lot!

Vince

Answer
Hello Vince, There is no way of telling if the belt has been changed until it comes a part. And I doubt anyone except a trained lexus tech could tell just by looking at the engine area. As far as if you can get the job done it is impossible for me to know your ability. There are a lot of parts that come off and a few tricks also. Most running problems are caused by the wires, cap or ignition rotor.