1998 ls1, converter won't stay in lockup

[99transamC/FIA]

have vigilanty 3,200 stall converter won't stay in lockup. Any ideas?
:ar:

[2001NBMZ28]

I've had a used Vig 3200 (out of my brother's car) for years in mine and never had a problem with it. Is it newly installed? If it's randomly unlocking at steady throttle I'd look for a misfire - any codes?

[SteveC]

I have a Y3000 coupled to 3.73 rearend gears, and after the install, I had lock and unlock problems until a dyno tune addressed these issues.

SteveC :)

[0rion]

misfire codes more than likely if it's locking and unlocking randomly. You can get it tuned out or go get a crank relearn done.

[bills98ta]

One more thing to check, the brake light switch... Ever notice while driving, if you tap the brakes, it unlocks the converter...
Just another thought, Good Luck !!!