Toyota Repair: 1992 Previa 4 cyl. std., spark plug wires, timing chain

Question
Does the 1992 Previa have timing belt or chain? What would be the approximate cost to change it?
The van seems to be lugging or jumping when it is just idling along but picks up great when you step on the gas.

Answer
It has a timing chain which seems to last forever, I have never needed to replace one, so unless there is a noise coming from the engine I don't think it's causing a problem.
Your problem is more lilely to be an engine misfire, check the spark plugs, dist cap/rotor and the spark plug wires.