Is it a manual or automatic transmission? 4wd? Where is the radiator located on it? Air filter location? What type of terrain your drive in? If it is steep and hilly, then try to check the power it has going up an incline...steeper the better. Lot of those automatic mini-trucks do not have much power to climb hills. 4wd helps but still some lack the power to climb a hill very well. 12 yrs ago parts were hard to find. Air filters were critical on those mini trucks, so make sure it the correct one and fits. We had issues with mini trucks when the filter was not the correct one and the air filter cover did not close properly. Got dust past the filter. Those trucks were not designed for off road, dusty type conditions.
I climbed in the blind one morning well before daylight on a hill we call the mountain, can see for miles in a couple directions. I watched my BIL leave camp in his mini truck, it had rained a little the night before so the roads were a wet but not bad. I watched him head south going down several inclines until he got to a dip in the road probably 20 yards wide and dropped down 8 foot or so in the middle. He got stuck in the middle of the dip and had to eventually turn and head up the draw a slighter incline than trying to go straight across the dip till he could get out. He then turned around and headed back to camp, got the the first small hill about 400 yards from camp and I watched him attempt to climb it 6 or 7 times..finally the the lights went out on the truck and as day broke I saw him walking back to camp. Not sure about all of them but I've heard many complain of the lack of power witnessing it first hand was enough for me to loose interest in them.