I bought this 2008 hyundai elantra on 4/27/2014 and the day after while i was driving home 50 minuts after leaving work the car jump/jerk and on 4/29/2015 almost a hour

try to unhook the positive on your battery for couple minutes this helps to reset alot of things and most of the time the radio is one.

run a cd disk cleaner disk thru the player. see if that will help?lol.

You need a transmission

axles boot, check the tie rod or ball joint

You got ripped off by the mechanic. A good mechanic can pinpoint the problem by using a scan tool. Take vehicle to autozone or similar and have it scanned for codes this will give you a idea what is wrong. I believe the problem is exhaust related because of the blinking light.

crank sensor will cause similar stalling issues. You may have got a bad alternator, if the battery light is on after you jump it, probably needs a new, new alternator. make sure all your connections are tight and plugged in, both on battery and alternator.

working with these types of tiures on a daily basis ive seen inexpereineced lads break the sensor mounted at the valve stem (inside the tire of course) if your display tells you which tire is low i would have it removed and inspect the sensor. that is if oyur pressures are set corectly, also there is sometimers a reset button and just plain driving around will someitmes clear it to normal.

look on bottom of radiator on the drives side of the car. Using a large philips screw driver turn srcrew counter clockwise until coolant begins to drain. afterwards. close screw and refill 50/50 water to antifreeze.

is the shifting due to the transmision? or the engine? i had a friend who's car did something simular, diffrent car though and a older model. turns out, it indeed was the fuel pump, when they thought it was the tranny. try some Lucas for the transmission. if that dont help then i would let the mechanic drive it.

5 qts. will be just right.