P0401 Code

I have a 98 Monte Carlo Z34 with the 3.8 engine. It has 109,000 I just had it's radiator, tranny and power steering flushed, new valve cover gaskets and new spark plugs. The car is running great but now I have a P0401 code. And now they say it has an upper intake leak. It says insufficient flow from the EGR, but does anyone have any suggestions where to start? I plan on cleaning the throttle body today. Also, what is the ball park figure of having the intake gasket replaced? Should I do the lower as well?

Cleaning the throttle body pintle and tube with a rifle brush and some Sea Foam Deep Creep took care of the Check Engine Light.:grinyes: The care runs even better now. I'm going to get a second opinion on the intake gaskets since I don't have any cooling loss, or anti-freeze in the oil. Any other suggestions on what I might look for?

Glad I was able to find this site. Hopefully, I'll be able to find some good, helpful information on here?????