Quick question for ya'll in regards to my "New to Me" Ne-izzon

Per the odometer ithas 89k. The previous owner had an exhaust installed, cat back w/ high high flow cat: -) and free-flowing muffler - In addition he installed an IceMan intake on it - he advised that after he installed the intake the engine has random hesitation @ engine speeds below 3k. It's nothing crazy to the point its going to stall, but more or less annoying. Doesn't matter if it's cold or warm and it is random. When I started playing with it I replaced:
-all 4 plugs w/ Bosch platinums, 3 of 4 were dry and tired, cylinder 3 was a little wet.
- New battery
- wires look good, those red AutoZone plug wires
- new battery clamps
- I've been running 93 octane (may be overkill but runs lsightly smoother prolly due to better combustion, and it's an older engine)
- new oil Castrol 10w-30 and filter

Don't know the condition of the O2 sensor and the coil pack on top of the engine...

Any thoughts guys?

 

Start by taking out the platinum plugs and replace them with some copper plugs.

He may have let something into the engine while trying to install the intake. Pull the TB and clean it off and since you mentioned one of the plugs had oil on it, you may want to consider replacing the spark plug tube seals.