Engine jerking, RPMs up&down

[xdviper]

Alright, Tonight after a cold start, The engine comes into its normal temp, I wait for 2mins before shifting into D and moving. After that, I hit the open road, and when I do, after I reach 30MPH, I keep my feet steady on the gas pedal, and I won't gain or lose my speed. Everytime I do this, the RPMs will be in the normal 15k-18k. But tonight, After I make a turn, mind you the engine isn't quite hot yet. the engine and rpm meter is jerking. You can feel it in the cabin. The rpm meter needle goes up and down. I uploaded a video to youtube so you guys can watch. Around 49sec up to 56sec, you can cleary see the RPM meter going from 2, up to 2.1 and back down. No I am pressing the gas pedal any harder. The engine sounds normal, it picks up normal. Maybe it's because Today I ####ed around with the 4WD Low and I heard that thud/boom sound, but after that I did go on a 30mile highway trip and there was notthing wrong....
http://www.youtube.com/watch?v=zf-8bgdlP-I

 

[Vinniety]

Alright, Tonight after a cold start, The engine comes into its normal temp, I wait for 2mins before shifting into D and moving. After that, I hit the open road, and when I do, after I reach 30MPH, I keep my feet steady on the gas pedal, and I won't gain or lose my speed. Everytime I do this, the RPMs will be in the normal 15k-18k. But tonight, After I make a turn, mind you the engine isn't quite hot yet. the engine and rpm meter is jerking. You can feel it in the cabin. The rpm meter needle goes up and down. I uploaded a video to youtube so you guys can watch. Around 49sec up to 56sec, you can cleary see the RPM meter going from 2, up to 2.1 and back down. No I am pressing the gas pedal any harder. The engine sounds normal, it picks up normal. Maybe it's because Today I ####ed around with the 4WD Low and I heard that thud/boom sound, but after that I did go on a 30mile highway trip and there was notthing wrong....
http://www.youtube.com/watch?v=zf-8bgdlP-I

You stated the motor was in normal temp but not that hot yet does that mean that when the motor is hot it doesnt happen? I have a 2000 sport and you can find a few threads that i started with this problem. I ended up changing out the upper and lower intake manifold gaskets and the problem is gone. It seems that it was a vacuum leak that causes it to studder at certain RPM ranges but when its hotter the gaskets expand and fix itself. Just an idea of mine.

Once again does it only do it when it is a warm motor and not hot or everytime. What kind of motor and how many miles do you have. I have 104k on a OHV motor. 28 dollars for the gaskets at carquest and a few hours did the trick.

 

[xdviper]

The engine wasn't warmed up yet, but now it's back to normal, this mourning I tired it, it was normal. I think its the gaskets just as you said.
I have about 141,400k miles on the car now. the tranny is acting up a little but I think later on this year, I'll buy a new 07 limited explorer.