engine valve noise under load

[jasonr73]

1992 astro awd ext, just flipped 100k and has valve noise under load. Not egr, not gas issue,not bad gas,not vaccum,not timing, absolutely puzzeled beginning to to think I need to remove the head. Only seems to make that valve noise under load, do not hear in park or nuetral. However after a night of sitting it chugs when started and then clears up, Can anyone help. :-k

[doyoulikeithere]

Just a FYI,
I chased a similar sound around and it sounded (from the drivers seat, driving) like valve noise - under load.
Eventually, I discovered it was the "Skin" on the catylytic converter was rattling, amazingly, only under load.
It was a 1990 GENI with the big flat style cat, and I have the same sound now coming from another, at least this time I know...
That skin gets rusted, develops a hole (not a leak) and then the skin can rattle against the body of the cat.
May not be your issue but worth a mention...

[Smiliesafari]

The element in the cat on my '96 came loose. It rattled too.

[1Gary]

If it is the cat,turning in your old one at the scrapper yd can be worth some cash to offset the replacement costs.