What did you do to your OBS GMT400 Tahoe/Yukon Today?

[the 18th letter]

Looks same rocker covers as my 97 vortec 350
Have you worked out what issue is?
If it is the same model as mine it may be inlet manifold.
Using any water?

I haven’t had a chance to look at it but I’ll start by checking the inlet. It’s got a small leak at the side of radiator I need to replace to be able to tell. 99 Vortec 5.7