Okay, so I have played the game a lot, and since the death of my 360 I was forced to buy it for the PC. 
Now, after becoming level 59 (and starting a new game with my Sheppard) I encountered a strange glitch - permanent weapon overheat. When I use a weapon to the overheat point it just overheats and that's it. No cool down. I can switch weapons, but the minute I get back to the weapon that overheated it's still overheated. This only happens once - for example when I load a saved game, I overheat my weapon and it's stuck, but the minute I load it again I can overheat it and it cools down again. It has something to do with when you start the game fresh (run the game). 
The overheating problem can also be solved by going through a loading screen (not an elevator but a door that brings you into a new area). 
 
I am just wondering, any idea if this can screw up my savegames for ME2?  (import savegames)
Thanks!

You're not using the High Explosive round as your weapon upgrade are you? 

I just read about this last night on the Mass Effect WIki : 
http://masseffect.wikia.com/wiki/Combat 
scroll to the bottom or read below
 
"It is sometimes possible for an enemy to be trapped in an unreachable location (usually, inside or behind a wall). This makes it impossible to kill him. Using Throw, Lift, or Shotgun with High Explosive Rounds can sometimes dislodge them. Alternatively, switching to the " Flying Camera" and shooting them from the location they are in, also works ( PC version only). If this bug happens inside a "zone", a base, mineshaft, etc. simply "zone out" or exit the structure and the enemy will reset it's position inside the zone. Otherwise returning to the Normandy should trigger the reset. "

i once saved a game while i was standing in  an elevator before it went down.  so next time i loaded it up, there i was, inside the elevator, standing on empty space with the door closed. fun. did i mention i was halfway into the game and i had to restart the whole thing?

On some machines, it is possible to trigger the "Overheat bug" that force the weapon to stay in its overheat state until reloading the game, or returning to the Normandy. This bug is the result of the Dog of War and Geth Hunter Achievements. The only solution here is to remove those achievements from the profile.

Note: A possible fix for this issue is deleting the profile file in the save folder ( edit: for some reason the pathway won't copy and paste- Documents/Bioware/Mass Effect/Save/Profile.MassEffectProfile ) and then reloading the save from every profile to rebuild the file and restore achievements. 

  You can also use the unofficial Critical Mass editor to remove the Geth Hunter achievement. 

how do achievements screw the game up? lol

Thanks! 
 
So since this is because of achievements, I don't think that there will be a problem with the carry over.