Random Drop in RPMs! Help?

My 2003 v6 Tacoma with 198k miles has been randomly dropping 200 RPMs when first starting to drive and when going 35 to 45 mph. I have replaced a fuel filter, a fuel pressure regulator, and a mass airflow sensor none of these things have seemed to fix it.

I have worked closely with my mechanic for the past year trying to fix it but can't seem to find out what the problem is. The only code that pulls is a p0741 which is the torque converter clutch solenoid getting stuck on or off. My mechanic does not believe this, or the fuel pump are the problems.

Does anyone have any similar problems or know where I can find some answers?

 

So your mechanic doesn't believe the code being pulled up is the problem? Sounds to me like they're milking you if that's true.

 

Sounds to me like your torque converter is locking up at low speeds when it normally wouldn’t. Also sounds like that code could be very much related.

 

Find a new mechanic

 

How are your spark plugs and wires looking? I had intermittent trouble with low idle and engine cut-off due to this simple factor years ago on a 230K mi. 3.4L.