Tranny controllers and lock-up converter

[Dr. Jalkal]

Does anyone have a recommendation for a tranny controller? 1998 3/4 ton 2WD suburban needs a MPG boost. My converter doesn't appear to be locking up. Tried hitting the brake during load and don't see jump in RPM. Any suggestions?
Thanks

[More Power]

Below ~62 mph, the TC will unlock when lifting off the pedal. When cold, the TC won't lock till the trans sees some temperature.

The vehicle's PCM controls both the engine and the transmission. To get a power/boost increase, it'll require a program chip for 1994-95 models or a replacement PCM for the 1996+ models.

Jim