Timing belt/Hesitation question....

I just replaced the water pump in my 93 rodeo, and went ahead and changed out the timing belt. Engine started up, after trying to crank it over a couple times and now it sounds great when running or idleing. Problem is, when I go to take off, it hesitates, and I almost have to floor it. Is it still a little out of time from the sound of it? Is this something setting the timing by timing light might remedy?

Also... I have an odd delima. My check engine light comes on every now and then, mostly after I have had it out on the highway or driven around for awhile. The check engine light will come on, and when it is in idle, it turns off. When I start going again, it comes back on. I would get it checked at autozone, and I would like to check what is causing it, but when I turn off the engine, it goes away and comes back at random, maybe not for a couple days. Anyone seen this before?

Thanks in advance for any input on these issues.

The first thing I would do is double check the alignment of the timing marks. Rarely does anything have to be adjusted if the timing marks are right on.