Still Surging

[RGuzz]

162k miles, TAP chip by PO, surges cold, intermittently when warm and 
cruising 3k RPM's mostly...new plugs, proper 02 sensor, TBV. Full boost 
@ 16 PSI for this chip, no vacuum leaks I detect. At times there is no 
surging at all. This is intermittent  seems not to be present under 
full throttle.
What do I look at next? The surging is annoying, feels almost like the 
AC compressor is kicking in but it's off, of course.
Someone suggested the ECU. But I don't recall this being noticeable in 
the past. This car has been mine since 148k miles.
Other problem is dashboard gremlins needs solder repair, bouncing 
speedo trip computer way off on it's readings. Is this related (doubt) 
to the surging?
BTW I also need an owners manual for this car...anyone know where I 
might find one?
Thank you.
Richard