This is concerning a 1999 Sonata, 2.4

I've been to multiple mechanics with this particular problem and I seem to get different stories of what the problem could be. One of the garages I brought my car to was the Hyundai dealership itself. Even the mechanic there had no clue what the problem is. His only response was, "Sonata's are shakers, its normal." Sorry, but I do not believe this...there is something wrong and I need to pin point what it is before I put anymore money into my car, orI end up with bigger problems down the road.

When I am at a full stop, while the car is running, the steering wheel and the dash starts to shake. When I put the car in neutral the shaking goes away.

I went to see a transmission specialist and this guy told me that this was NOT a transmission problem, but an engine problem. He told me that the shaking is my engine being off its timing. So is this linked to the timing belt??? I changed the fuel filter, spark plugs, and used injector cleaner additives in my fuel and the problem has still not gone away. So like I said, "could this be linked to the timing belt??? Would a miss aligned timing belt cause the steering wheel and dash to shake when I am stopped at a red light, and when I put the car in Neutral the shaking stops???
I checked the timing belt and in my opinion the belt seems to be loose. The belt itself is in great condition BUT it also looks like one of the gears is tuning slower then the gear next to it. Could this just be me thinking this or couldit be a possibility that one gear is turning slower then the other???

If this is NOT a timing belt problem what other possible factors could be causing this shaking problem???

I have recieved other advice concerning this shaking problem but I am not 100% sure on how accurate that advice was? You know how garages are out to make money!

...any advice would be much appreciated!

 

...oh by the way...there is a pending code that showed up when I had it checked a few times when I had "check engine's" for other problems. The pending code always was the same and I was told by multiple mechanics that this was nothing to be concerned about.

The pending code went as follows, "P1520 Manufacturer controlled vechile speed, idle control, and auxiliary input."
Could this be what is causing the "shaking problem" I am experiencing???

 

I dont know about the engine code, but timing belt problems are common with Hyundais. When was the last time your belt was changed? They need to be changed every 60,000 miles, or they can snap and break your engine completely. My advice would be NOT to go to a dealer, but to a smaller, local mechanic. They usually will be able to give an objective, outside opinion. Dealers just wanna make more money and can be full of ****! But I would think it very well could be your timing belt. I will ask around with some of my fellow import drivers and see what I can find out. best of luck