Should I be worried?

[Bernard96SE]

Today, my car was acting weird. Revving wasn't smooth, and when floored it wouldn't go past 3800 RPM's, I had to back off the throttle to get it past that point. It also made very little power when floored, but ran fine at about 3/4 throttle. While traveling down the highway between 70 and 75 mph, there was a near regular lurch, very slight, but definately noticable. Also, moving the gas pedal had little effect, until it hit about half throttle, then it kicked like I just hit the nitrous button, except I have no nitrous. The car was making fine power, but it wasn't smooth at all, and the biggest irregularities seemed to happen in the 3000 RPM range. Though I could be wrong, this was happening on the highway.

The weird thing is about halfway home (about 75 miles of this problem going on), it just disappeared. Gone, car is running smoother than butter.

I have just recently (last weekend) replaced the wires, plugs, rotor and distributor because it was having this problem after it had sat for about a month in the body shop. Only it was a lot worse before I fixed it, like wouldn't rev at all. It just baffling me how this crept back up again, and then just disappeared.

Any ideas?

[96ProbeSeC]

My car has been doing the same thing recently. 90% of the time it will run perfect, but sometimes it will just like bog down. There will be very little throttle response until you either floor it or untili t works its way up to just past 3000 then BAMM it hits like a rocket. Any probable causes and / or solutions? Also i have noticed this happens more often when i have the AC on...??!!