Jerking when driving uphill, accelerating

I have a 2004 Hyundai Elantra with 130000+ mi on it. The current engine has 96000+ mi; the original was replaced because the previous owner allowed it to overheat, blew a gasket, and apparently warped the engine itself.

I have owned this car for about 6 weeks now. The car was driven roughly 160 mi from where it was purchased to my residence; no trouble on that trip. However, within the first few weeks of owning it, the car started making a squealing noise when I turned the steering wheel. I took the car to a mechanic and had the belts adjusted. This eliminated the squealing, but I was also told that the CV boot needed to be replaced (they asked if I had been hearing a clicking noise when turning, which I had but had thought nothing of), so I also had that repair done. Problem solved. Car seemed to be running fine.

Okay, on to the current problem. Something else I had started to notice, before I had the belts adjusted, was that it seemed to hesitate a little when going up hills, and sometimes when accelerating. It was a small thing, and I attributed it to my driving style (which probably isn’t the best) and the fact that my area is very hilly and the car might be having a harder time with that. Well, this problem has gotten worse; I can definitely feel the car jerking, especially when accelerating (very noticeable when going uphill). The problem also seems to be worse at lower speeds, but I’m not entirely sure that I’ve nailed that down.

I don’t know much about cars and their workings, though I’ve been trying to educate myself. I worry this might be a transmission issue, because I’ve had that before and it feels a little similar. I’m also thinking it could be a fuel issue. One thing I noticed is that it seemed to become much more noticeable after the last time I gassed up the car. It seems like it’s getting worse as the fuel is used up, but that’s probably just a consequence of using up fuel as I drive and I’m just looking for connections where there aren’t any.

Anyway, this is a weird history/set of symptoms, so I’m not sure if anyone has any insight, but I’d appreciate it. I have an uncle who is a mechanic that I’m also consulting about this. He replaced the engine and did some additional work; unfortunately, he’s in the city I drove the car from, so not really within a reasonable distance for helping out with car trouble. In any case, thanks a lot for any help!

I suggest finding a good local mechanic. Not a chain operation. Chains tend to be less knowledgable and will likely cost more in the long run.

You need someone who can do a hands on inspection.  

While it could be several different things, some might not be expensive, but you have a few symptoms that sound expensive.  

While many of us may be able to make some suggestions and may well be right, but you really need to have a good mechanic (I suggest avoiding any chain outfit.) 

Good Luck

Thanks. I’m a bit leery of bringing it back to the shop I went to previously; I don’t think they did a bad job, but I think I was overcharged a bit. However, a good friend of mine has suggested a place that he uses and trusts, so I will probably give them a shot. Just thought I’d see if anyone could give me some insight ahead of time. Again, I appreciate the input!