first gear slips out to neutral when slowing to a stop,then if i don't wait a bit before taking off trans pops into first hard. will service cure this or a new throttle position sensor?

If you have an automatic transmission and it "slips" while you are driving it—that is, the car engine revs without the power going to the wheels—the most common cause (though not the only possible cause) is low transmission fluid. If the slipping is caused by low fluid, it will get worse as the transmission gets hotter

The next question is, why? Probably because you have a leak. Maybe you have noticed red transmission fluid in your driveway or your parking spot at work, but it didn’t occur to you that it came from your car. The cause of your leak is probably a failure of one of the seals that keep the oil inside the transmission (though there are other places the transmission might leak). How many seals the transmission has depends on whether you have a front-wheel-drive, four-wheel-drive, or rear-wheel-drive car. If you do have a seal that is leaking, and you catch it in time before it damages your transmission, there’s a chance it might be relatively cheap to repair. Seals themselves are not expensive parts, but depending on where they are located, it might take a lot of labor to replace them.

Sometimes when an automatic transmission is low on fluid and you top it off, air pockets develop inside the transmission that keep the fluid from getting to all the parts of the mechanism. After adding the fluid, I suggest that while the car is running, you move the shift lever through the different gears on the shifter selector, and then check the fluid again. Running the shifter through the gears redirects the fluid to different parts of the transmission and removes the air pockets. You may have to do this procedure several times, or even drive the car around the block, and then recheck the fluid level.

Im having the same problem. just had trans fluid flushed and filled. leaks fixed. still When I come to a stop, and go to pull off, it doesnt react it doesnt rev on its own, only when i step on pedal, if it doesnt catch right away I let off. then after a sec or two it will catch. any ideas, help is appreciated.

Automatic transmission. Gear at D. Position automatically switch to natural while driving. Or. Approaching at stop light possible transmission control solenoid / Transmission shift solenoid bad & suddenly stop working . & suddenly. Work again .