V6 stumbling/bogging (1993 90)

[Chris Newbold <cnewbold@transarc.com>]

Well, with the sudden return of summer-like weather, a gremlin has
gotten loose in my 1993 90...

With ambient temps. around 80F and the engine hot, it stumbles and
bogs badly if I snap the throttle open around 2100RPM in 2nd gear.
There is a pause, almost like a power loss, and then it surges
ahead again and runs a little rough up through 3000RPM and then
seems to be okay.

More delicate throttle application doesn't elicit any symptoms.
When colder, it runs almost fine, except for a little raggedness
around 2800RPM.

The O2 sensors are fairly new, about 15,000 miles and 1 1/2 years
old. I checked for obvious vacuum leaks, and all hoses and tubes
seem to be intact and in good condition. No codes in the ECU.

Anyone have any suggestions?

-Chris
1993 90CS 63k mi