hi
i have a 1993 j30 with 335000 kms, no its not a typo, car does 200 hot kms a day. On a hot restart i am getting rough running which sometimes clears after 10 min, always ok on a cold start. Mechanic thinks i have a gummed up hydraulic tappet. Any ideas on how to identify and clean, I dont like the thought of changing them all.

 

do you have the 24 valve motor?
there are engine flushes you can run through. HOWEVER you have a rather significant risk of getting leaks because of it.

 

Mechanical noise can be listened with stethoscope. DIYscope: Screwdriver on the engine, ear on the screwdriver handle.