if you can find it cd-2 makes a fuel additive in a multi-dose squeeze bottle.if i remember correctly it was about 2 oz to 10 gallons.one dose got rid of a slight skip in a maxima i owned in less than 1/2 tank of fuel.good stuff just hard to find.
Using it before an oil change makes sense, but before *each* oil change? cmon..that seems more than a bit excessive. I suppose it would depend on what you're oci is as well.
Although, I have to ask: if you're using good quality fuel like Chevron w/ Techron or V-Power, why would you need any fuel additive at all?
Injectors flow spray reduction, valve buildup, intake buildup, carbon buildup on pistons, PCV/EGR crud, ......starts the minute you start your car. If you are not using a toptiergas.com, you are very likely going to need an FI cleaner at every oil change.
I've pulled plenty of injectors and intakes. You'd be surprised how quickly crud builds up.