FFT, padding, IFFT and plot in time domain

Hi, I performed an FFT with some zero padding and would like to transform it back to time domain. When I plot the signal it looks wrong. Is it because of the padding used in the FFT? How can I make it right? here is my code for doing the IFFT:

   NFFT=4301;
   AvIFFT = ifft(FFTavg.dat,NFFT);
   plot(real(AvIFFT))

And I get this plot:

Any help would be greatly appreciated! Thank you!