I have a 1994 Toyota pickup 3.0 automatic. I've just got the thing put back together after a headgasket job and now I have a major problem. I was going to take a test drive in it before I put insurance back on it and then boom.. the truck is in time perfectly and isles fine but as soon as it's about to shift into second gear I lose all my throttle. I can hold it to the floor and nothing changes.

 

Consult your manual. In the automatic transmission section is a diagnostic flow chart and trouble shooting guide.

Run the manual shift tests to verify the transmission is general healthy, then go back to the top of the flow chart