So I noticed a rattling sound from under my 2002 Blazer, couldn't hear it from the front, just underneath near the cat. Oh not the cat again I thought as I had replaced it less than 30,000 miles ago. Well ill deal with it this weekend I thought. Then yesterday I noticed a loss of power. It got worse later on my way home from work, really bogging down even stuttering at about 2000rpm. There were no codes.

Pulled the cat today and couldn't find a problem. Can see right thru it. Put a straight pipe on to test and still rattling and power loss.

Pre cat? Hit it with rubber mallet and no sound. Stuck my shop down it and nothing came out.

Clutch bearing? Nope. In or out no real change in sound.

Stumped. Went to Google and too many things popped up but after an hour of searching the distributor caught my eye. I checked mine, a little build up but nothing bad. Cleaned it up and checked ignition wires (rotor, cap and wires changed last year).

Moved on to the coil. Ok that's a part I haven't replaced. When I grabbed it moved, to be more specific the plastic part would wiggle inside the metal squares of the coil. Strange, maybe someone can tell me if this is normal.

Anyway I checked and cleaned all the other connectors. The only issue I could find is when I checked the MAF and noticed the aftermarket snorkel was broken away from the mount. Just a cheap aluminum bracket, I made a new one out of steel. Cleaned the air filter and tightened up the clamps.

Guess what, rattling and power loss is gone.

Maybe someone could tell me why and answer the question of if I need to replace this coil or not.