96 caravan "hesitating" on steady speed

My 96 caravan "hesitating" on steady speed.
I changed the fuel filter,flushed the injectors,new spark plug and new wire set,new egr valve and i checked on the onboard computer and I didn't find a codeset.I also did a diagnostic test and I didn't find any problems.

Does anyone know the problem?

I had a simular problem like this. The problem was that the inside of the throttlebody was coated with black sooty carbon build up. It gets this way because the PCV valve sucks in engine blow by gas and this will clog up air passages in the throttle body. You may notice that the idle is "floating" rather than steady. Use liberal amounts of carberator cleaner on the inside and outside of the throttle body.

Yogi_123rd is right, but....

Are you running your air conditioner? this will cause a momentary lag or hesitation, and sometimes even try to drop the van out of overdrive. It has a lot to do with the condition of the a/c compressor and the overall condition of the van's engine. The more worn they are, the more prevalent the condition will be. Aside from being annoying, it's fairly normal to see this happen.

Also, you might consider a dealer's "combustion service"(not fuel injector cleaning) this could also solve this condition.

I think I had the same problem. When at steady highway speeds it would hesitate - kind of jerk you. After seeing a competent Dodge mechanic I learned it was going to be either the MAP sensor or a more expensive transmission repair. I replaced the MAP sensor. That did it and it's still running perfectly after one year.