Deceleration

I have a 2005 hyundai tuscan. It doesnt have any problems just driving around town, but when we go on a trip, say at least 100 miles, when we go up an incline, the car rapidly decelerates. If I try and give it more gas, it’s like it is getting none at all. Then after awhile, it kicks back in and accelerates again. Help!!! Any ideas?

When did you last replace the fuel filter?

Even if the maintenance schedule for your Tucson does not mention it, you need to replace the fuel filter at least every 3 years or 30k miles–whichever comes first.