I would try all of the following:
- Make sure there is nothing obstructing the air flow through the air intake
- If its been a while, replace your air filter while you're in there
- Clean your MAF (if you're not sure how, there have been a number of posts about it)
- Clean out your throttle body (I believe this is a doc in the how-to's about this)
- Toss a bottle of fuel injection cleaner & octane booster into your gas tank
- Make sure all the connections to your battery are firm & free from grime / grease (If the contacts are dirty, a spray can of electrical contact cleaner should do the trick)
All in all, including the air filter, this should cost you < $40, take about half an hour, and could do WONDERS in addressing your problems. I was experiencing weird hesitation and idle in my SVX and the above did the trick.
The 4 gauge alternator mod can also prove helpful in leveling out jumpy idle or other quirky electric behavior.
Good luck!!