sounds like its running on 3 cyl?

hello everyone I am new to this forum and I would appreciate any suggestions that anyone could give me. so heres the deal, I own a 1997 tacoma with the 2.7 L 4 cyl, and when I go to start the engine up in the morning, the car sounds like it is running on 3 cyl. however when I accellerate it keeps on acting like that for about 30 seconds and then it goes back to normal. so what do you think is my problem and what can be done about it.
thanks again,
Mike

Don't post the same problem in more than one forum.