V8-Surge betw 2K and 4k rpm

[Dick Krucker <dickk@postsfo.speedware.com>]

Help, I'm making Nortland Audi rich. They have helped me out by working   
on a # of problems:
1) Replaced Ox Sensor under EPA warrant Car 91 V8 has only 34,000 miles 
2) also replaced all 8 fuel injectors 
3) Just replaced 'Speed Sensor" as they were getting Fault #28 all the   
time. 
4) I did install a K&N air filter 1st thing when I bought the car. 
5) Starting problerm was cured w/new Pressire Valve on Fuel Inj. sys.  
6) iI've run so musc fuel injector cleaner thru I might own Chevron.. 
   I am at a loss to the problem. The tach seems to come to a stand   
still, then goes then stops till 4,000rpm then everythinh clears up and   
runs like aBanshee!!!!!!
If anyone has any ideads I would welcome them...I sent the dealer one   
article that I found in the Archives about a loose wire between the ECU   
on the engine and the ECU on the tranny. He said he didn't think that   
they were connected, but would check it out. That was yesterday....
Please send to all response to dkrucker@speedware.com
Thanks for your help.....