What would cause my van to start to accelerate.. then stop at 30mph.. then continue and stop again. Will stop and go whole time I hold gas down. Could a fuel treatment solve this? Maybe it because I've used a lot of cyphered gas? NEED HeLP

Joe, let us know what you're driving. I'll place a sticky at the bottom. It really helps us to help you.
So you're saying it will accelerate up to 30 then just quit accelerating?
So after 30 it will like surge on-off-on-off, like that?
https://www.askmehelpdesk.com/cars-trucks/when-asking-about-your-vehicle-303903.html

Im driving a 1989 plymouth voyager 4 cylinder Turbo.. and yes that's what it does. Say I was at a stop sign and floored it, it will go good until around 30mph and then surge on and off like you said. It isn't dying on and off.. just acceleration

Some suggestions
I would look for unmetered air coming from the air induction.
Such as a torn intake hose leading to bad motor mounts and such.
Bad throttle positions switches, crank sensor, faulty ignition coil

ICM or coil breaking down under load? "Cyphered gas?" Compression issue?

Someone is telling me it is my timing belt.. possible? But I can't get this pulley off http://www.flickr.com/photos/59881073@N06/5469857418/ do I need a special tool?