Engine/Transmission (1994 - 1998) TC falling out of lock-up?

[Texis]

My torque converter falls out of lock-up and immediately locks back up, jumps up about 250-300 rpms... then right back down? It's 1-1.5 second event. Has happened 2 or 3 times in the past couple of weeks, any ideas what could cause this? Electrical, vacuum... what locks it up?

I am assuming that this is the TC lock-up function, based on the amount the rpm is jumping.

 

[Texis]

I see from other recent threads the issues here are; TPS, bad grounds, bad battery, trans temp sensor. I'll start with these if the problem persist.

One thing I have learned about driving 17 year old trucks with 400K on the ticker is you don't do anything about new problems until they continue for a while... as they often go away on their own!