This problem you have is absolutely common to the SVX. Before you start paying to have things replaced or diagnosed just grab the codes from the ECU which you can do in about 5 minutes. Even though the check engine light is not on it'll still have the codes stored. 9 out of 10 times based on your symptons you'll find that it's your MAF. If your want to check your alternator there a quick and simple way- start your engine disconnect the battery cables and wrap them in cloth so that they can not touch metal start your light and accelerate the car to about 2500 rpm if there is any hesitiation then your alternator is weak and needs replacing. IF not then odds are again that the MAF is bad. GRAB the codes from the ECU before you do anything! It'll save you a ton of money and headache.