'94 SSE with 145,000 miles.
Bosch platinum 4+ plugs put in 1 year ago.
K&N Air filter.
Plug wires 5 years old but good quality.
Replaced 2 coils 2 years ago, 3rd is still original.

Symptom:
When step on gas pedal car engine sputters.
Happens in both park and drive. Less noticeable in park.
Seems to sputter more when engine is under a load (e.g. going up a hill).
For 3 years I've heard a lower engine knock noise that may be bearings or balancer.

Any idea?

(p.*. I'm the kind of guy that keeps all the receipts for all parts replaced and has replaced most of the parts in this car)

Start off with checking the plugs. For some reason GM'* DIS waste spark system eats Bosch plugs like they are soft chewy candy.

After that.. give the old vacuum hoses a spray with carb cleaner and listen for any changes in idle to locate possible vacuum leaks.

When that fails.. Let'* check over the rest of the ignition system like ohm testing the two leads on each coil and double checking teh plug wires to make sure they don't look old, arching or bad.

Sounds ignition related from your description.

I don't want to pull of each coil and do an ohm meter check. I vaguely remember an easier way of checking but can't remember. Is there and easier way to check if coils are bad? I thought you just pulled off one or both plugs and if it arcs between the 2 coil posts that is a fast check.

Also, I've never in my life had a bad spark plug wire.
How do you test if these are bad?

What about O2 sensor?

After I check all this and still everything looks good what is the next step to troubleshoot?

Well Doug I see no one has replied to you. Much better website when willwren ran it. But, hey, I'll be so kind to answer you. You take that think out, slap some grease on that baby, slather a little **** on that sucker and watch that ****** move.

i'd say that its the bosch plugs. you can't go wrong with ACDelco'*. Next, I'd check your vacumme lines, coil packs, and fuel pressure. if the engine'* not getting gas (higher rpm'* need more gas) then it would sputter as it leans out.

good luck!

I put those Bosch Platinum Plugs in my 98 ssei. The moment I put them in it seemed like it ran worse than it did with the 5 year old AC Delco plugs. A year later I pulled them out and replaced them with the recommended AC plugs and it ran perfect. The whole time those platinum plugs were in there it aggravated me that the engine didn't seem to run like it should. I would never buy them again!

Should never use platinum plugs in a supercharged car. The don't do well with the high pressures we have. One of the best plugs is the Autolite. Only cost about $1.79 each and work GREAT.