LS1 stumble between 1500-3000rpm

[99WS6formula]

my 99 WS6 (T56) has developed an intermittent stumble between 1500 & 3000RPM, mostly noticeable in 2nd & 3rd gear under moderate accelaration. Just off warranty, it has only thrown codes once and that was for defective O2 sensors over a year ago. (The code was reset at the time by dealer and never came back-O2 sensors were not replaced). Otherwise I have not had a single problem. I now have about 35,000 miles on it, totally stock except for K&N and am raring to up the power but would like to figure this out first. Fuel filter and K&N was changed/cleaned a month ago and regular maintenance has been done over the last three years..... I am taking it into the shop but was curious if anyone out there has had/heard of a similar problem???


Cheers!

[FRMLAV8]

I have been noticing a similiar problem on my 99 TA lately. I am thinking I may have to change my plugs and wires again.

Let me know if you find out anything definite!