Troublesome Latex Table

[agro]

Guys, look at this troublesome latex code:


\begin{tabular}{|l|l|l|l|}
\hline
foobar&\multicolumn{3}{|l|}{yadda yadda yadda yadda}\\
\hline
z&2&3&4\\
\hline
\end{tabular}



\begin{tabular}{|l|l|l|l|}
\hline
foobar&\multicolumn{3}{|l|}{yadda yadda yadda yadda}\\
\hline
z&2&3&4\\
\hline
\end{tabular}


I want to make the columns that contain either 2, 3, or 4 have the same width. However as you see above, the column that contains 4 is wider than the rest.

Is there an easy way to get what I want?

Thanks a lot!