While driving my 1999 Lexus ES 300 as I speed up or slow down it jerks then level off. What could be the problem?

SOURCE: intermitent electrical shut off

Asked a local independent Toyota/Lexus repair shop.

He suggested checking battery cables at both ends to assure tight fit.

Positive cable was ever so slightly loose.

Tightened all cables. Will see if that solves problem.

SOURCE: car keys locked in trunk of 1999 lexus es 300

1. I presume your button on the dash (which opens the trunk) is not working. You could take that button out of the dash panel and manually activate the circuit by using the wires themselves.
2. If the "valet" key doesn't fit the trunk lock, see if the keys are visible through the center back seat access 'hole', make a wire hook attached to a broom handle, etc. and try to catch the ring the key is on. If the view is blocked by other things you can't move, figure out at way to move things in the trunk so you can get something to reach the key(s). Do you have other metal keys on the same keyring? If so, use a magnet to grab the whole set.
3. Have you considered taking out the rear seat? Do the bottom seat cushion first, then the back.
4. By now you have hopefully already gotten your keys back out of the trunk, but if not I hope one of these suggestions works. MW

SOURCE: after driving 22 miles the car slows down

ENGINE COULD BE GETTING TOO HOT.CHECK ANTIFREEZE LEVEL AND TRANSMISSION FLUID LEVEL.

SOURCE: 1999 Lexus ES 300, trying to locate the speed

on the transmission next to axle right hand side

SOURCE: check engine lights came on,

A constantly blinking check engine light means you have a misfiring engine that is bad enough to cause your catalytic converter to go bad! Take it to the shop... probably means ignition parts and the upper manifold has to come off... and that's no fun! Good luck.