"Low Rider" by War
Bass part by Francisco "Poncho" Tomaselli (War)
Tabbed by Dan Bogosian (UtBDan)
Visit UtBDan's band at:
http://www.geocities.com/underthbed/

Strike of the cowbell, then:

G---------------------|
D-------------3--5353-|
A------1-3--5---------|
E-1-3-----------------|

G-------------------35-|
D-------------3--535---|
A------1-3--5----------|
E-1-3------------------|

G----------------------|
D-------------3--53575-|
A------1-3--5----------|
E-1-3------------------|

It plays all these riffs, and as far as I can tell there is no real pattern.

This is far more accurate than any other version up.