hi have encountered another problem with my toyota supra n/a 1991 model at start up she has a rattle sounds like either a valve or hydraulic lifter but when car warms up sound almost goes away you can still just hear it when you rev up through the gears doesnt affect acceleration and now when car is sitting i rev it up when it reaches 4000rpm the engine vibrates could this be timing as car is so quiet otherwise any help would be great

Well, first off the 7M doesn't have hydraulic lifters. It has shims that sit between the cam and valve spring. What have you done to troubleshoot the problem? Have you popped the hood and had a look around. Have you listened to the car from the engine bay, under the car, etc. to pinpoint exactly where the noise is coming from? Check some basics and post more info. It could be a lot of things.

have listened under the hood and the noise seems to be coming from the front of the engine next to the distributor rattles away till car warms up about 2 to 3 minutes then goes away when i drive the car it makes a kind of rasping sound but only if i put the foot down could this be a bent or worn valve forgot to mention the exhaust manifold has a slight blow at start up

When was the last time the valve clearance was checked?

have no idea when the valve clearance was checked when i bought the car last owner said it had a reconditioned engine put in 7000 miles ago along with new timing belt so never thought about that one will get a mechanics advice thanks for your time