I carried my 1995 S10 Blazer to my repair man with a coolant leak, found that it was a freeze plug leaking, no problem taken care of with some stop leak. I pick it up the same afternoon, but now it has a valve sounding knock that I did not have before that time. He put some Lucas fuel additive in it, and said my oil is way over due for changing. (true) it is also running rich, anyway changed the oil and put a quart of Lucas oil treatment with it, engine is still knocking, running rich, sounds like a miss also. checked my fuel pressure, it is 58, book says that correct areas. Help not sure what else to do...

Ok... This sound... Is it a tick, like tapping a screw driver point on a table, or is it a knock, like tapping the handle of a screw driver on a table? If it is a tick, then it mostlikely is a stuck hydraulic lifter. If it is a knock, mostlikely it is in the bottom end and will only get worse...

What ever became of this knock noise?

Yes, I was wondering much the same...

ok, time for a update, I found that I had a leaking fuel regulator, a pin hole in my fuel line, and all this extra gas was going into my oil. There was an eailer post about this same problem. I am still wating for my parts to come in, but I think the gas just thined out my oil and caused a knock, that before that time I never had. thanks for asking about it

wow I'm glad I found this thread, I think its teh same problem I have with my fuel spider and fuel-pressure regulator....thanks :)