Toyota Repair: Valve Noise and Shudder, engine misfire, octane gas

Question
I have a 1988 Camry 4 cyl auto with 119000 miles.  The car is in great shape..but I have two problems.  First the valves chatter under load.  Second..the car shakes when in drive with the brake on.  The shake problem can almost be eliminated by putting the car in nuetral.  Any idea about what might be causing these problems?  Thanks.

Answer
I'm not sure about the valve noise, it may be nothing more than pre-ignition(pinging)make sure the timing is set correctly especially if the timing belt was replaced recently,try a higher octane gas and see if that helps.
Unless there is an engine misfire the shaking is probably due to weak or collapsed motor mounts, the mount in the front near the radiator and the upper link on the right front fender(looks like a dog bone)check to see if the rubber insulator is cracked ,if it is replace both mounts.