was looking under my 96 astro the other day and noticed some kind or motor under the van below the driver seat. what is this for?

the converter is welded so there is no way to disconnect the front half of it.

my 96 astro is really running rough, bogging when I step on the gas. I pulled codes p0101,p0102,p0300, and p1406. the misfire and MAF codes I am assuming is from a earlier problem which was solved by replacing plugs, wires and cap and rotor. I never erased the codes as the SES light went out on it's...