[Demps]

I'm not a fan of throwing parts at a problem. It's not too hard to pull the plenum once you've done it so here's my technique:

I assess ignition wellness by monitoring for a miss, wire integrity, coil resistance, plug condition...to start with. I've found: drive the car a gear high in steady cruise and gradually/slowly add throttle. If it misses, odds are you have an ignition issue--Plug condition or gap, wires or coils.

So, if you suspect any ignition problems you could change the coils...but you may find it's the wires or plugs. A free check is to check resistance across the coil posts and then across the wires paired over the coil. Plus change the plugs.

Ted