> surging... the power would be there, and then go away... in about 5 second
> cycles.
> 
> - I went through fuel really fast... like 3/4 of a tank over the last 90
> miles. 

Before going thru a lot of work, check the tail pipe for soot.  If
black, disconnect 02 sensor.  See if that doesn't take care of the
problem.

TBill
***Always suspect the 02 sensor***