Not all .mp4's are alike. Premiere Pro is designed to work with a specific subset of the MPEG4 standard, it may well not work with all.
You're best option is to use original media you shot yourself using a supported camera format.
Welcome to the forum.
What is the source, or sources, of the MP4 files?
What are the properties of the file(s)?
Well, I tried what John T Smith suggested and the video did help somewhat. I created sequences based on the clips themselves; the shakiness of the video is gone and now Premiere shows that it is completely rendered and should playback in realtime.
However, the audio is still out of sync. I tried converting the .mp4 format to other ones like .mov but I am still getting the same audio issues.
Problem is, I did not shoot these myself. I was given the film footage by my instructor for educational purposes and they are all in .mp4 format, so I cannot use the original media if I wanted to.
Well, you might try explaining the situation to your instructor. Maybe have him give you media that works better with Premiere Pro.
Read Bill Hunt on a file type as WRAPPER http://forums.adobe.com/thread/440037?tstart=0
What is a CODEC... a Primer http://forums.adobe.com/thread/546811?tstart=0
What CODEC is INSIDE that file? http://forums.adobe.com/thread/440037?tstart=0
Report back with the codec details of your file, use the program below
For Mac http://mediainfo.massanti.com/
With more information, someone may have an idea that will help
Some muxed (Multiplexed - combined Audio & video) MPEG files can be problematic.
When that happens, it's often best to rip the Audio from the MPEG with a program, like Audition, Soundbooth, or even the great little free Audacity. Then, just Save that Audio as a PCM/WAV @ 48KHz 16-bit, Import that into PrPro, and just Mute (Audio Mixer), or turn OFF the Audio Track with the MPEG Audio.
For some tips on syncing, this ARTICLE might prove helpful.
I tried your method Hunt, but no luck... I synced the video and audio, and it worked for a few scenes, but as I scrubbed, it was out of sync again.
Is it possible that there is something wrong with Premiere itself? Since nothing I tried was working, I ripped a DVD onto my Mac (I downloaded the other .mp4s from the instructor's website). Initially it worked perfectly, until I briefly scrubbed and now the audio is out of sync. I tried deleting the Premiere file and starting a fresh one with a new import but it remains the same. How did it work before and now it is the same like all the others?
I may just have to manually align the video and audio as I need the clips but there has to be a way around that.
My guess would be that your files are 'different'.
In QT you can do (Window > Show Movie Inspector) to see the various Codecs/Sizes etc.
Since you stated that everything is OK when you play the files in QT - this says to me that your first step should be to use QT Pro to export all your clips to the same Format/Codec/FrameRate/Size etc. This will allow QT do to whatever it's doing to keep it all in sync and give you a file that's in sync. Once you bring these files into Premiere you'll notice that your editing experience will be much smoother and more enjoyable. You'll be able to forget about "Why's my machine acting up?" & get on with editing.
A lot of people want to spend way too many hours on why it's not working instead of solidifying a workflow that does work.
In the time it takes to post to the forums and get tons of responses of try this, report back - try that, report back... you can export your clips from QT and be editing.
I've found this workflow works on Premiere, FCP, Avid, & Vegas.
Wow, a method so simple, but it worked! Kinda odd how Media Encoder could not fix the problem but QT did. Just in case, I tried scrubbing and cutting back and forth to see if any issues arose, but the video/audio stays in sync. Thanks, I will definitely use this in the future!