2002 protage 2.olt hasites under load but clears up after 3000rpm

You are dealing with a misfire.It clears up at 3000.RPM A jump timing belt can do this or a broken valve . Also a failed coil pack. Lets go with a failed coil pack.Because of the strategy that is used a failed on the engine smooth at 2000RPM (neutral) No. 1 and No. 4 are fire simutaneously and No. 2 and No. 3. simutanueously. with the engine running lift the plugwire to number 4 does the engine stumble if it does this is the working cylinder and there is nothing wrong go to number 3 you may have to use number 2 engine running wire pulled out does the engine stumble if there is no change you found the problem.Basically what yopu are doing is checking for spark at all the cylinders