Car Jerking 2004 Santa Fe

I own a 2004 Hyundai Santa Fe with a 2.7 Liter engine with a AWD four speed shiftable auto. Now, I’ve noticed recently that sometimes going up hill or on take off, or using “Sports Mode” (a.k.a the shiftable in shiftable automatic), the vehicle will actually sort of jerk one or two times, usually two. Not it’s not lurching forward, it feels like it’s jerking back almost, and it’s happening slightly more often than it used to. My guess is that is the transmission, since before I owned the vehicle, it was my mom’s and she never really did any preventive maintenance other than oil changes, so the ATF hasn’t been replaced in over seven years. It also has near 236,000 miles on the odometer, although it is on a second engine (timing belt broke once, destroyed the whole engine), so I’m kind of in over my head here, transmissions are definitely not my specialty. Quick note though, the spark plugs or wires have not been replaced since the new engine was put in, and that was back in 2015-2016. Any ideas what’s going on?

Change the ATF and see how that goes.

I’d also check the fuel pressure in case the fuel pump is starting to fail.

Here’s another vote for changing the trans fluid, if you’re lucky it will be a simple drain & fill , no filter to change.
A drain and fill on my wife’s 02 Sonata was 5 quarts

If yours works the same just measure how much drains out. If things haven’t changed the only place to get the fluid is at a Hyundai dealer and they are very proud of it.

Hey, thanks guys, I’ll check it out, I honestly didn’t want to do a flush on it, though, I have heard that sometimes if the fluid has been in there for a while, that if you put in new fluid it may start to slip, although I am not sure of the validity of that. I’ll also check out the fuel pump.