I have a 1989 Dodge raider . They're same as a Montero. I had a problem with the engine running rough and cutting out on acceleration . It was electrical . I replaces the ignition coil , Distributor cap , rotor and spark plug wires . That fixed the problem with poor idle and acceleration . But not the valves tap loudly upon acceleration. It idles and revs in neutral without incident . Is it a timing adjustment? Could it be a bad or wrong coil ? I also test drove the car after installation of parts with one sparkplug wire unconnected . Can you damage the piston doing that? Please help if you can .

 

test oil pump and oil ways, replace hydraulic lifters or adjust manual type.