As the members may recall, I replace the intake plenum on my 98. It ran great after I did the work until recently when I had the problem with the MAF sensor. I took the intake completely off and did a very good cleaning; without any of the sensors, and then reinstall. It ran great for a few days and then the same issue of the idle dropping low and the hesitation on pulling away at stops. I put a new throttle body gasket in place and I noticed that I can see the gasket on the left side (towards the front) between the plenum and throttle body. Should I be able to do this? The plenum was a Dorman. The check engine light is off.

yous sholds poats de photographs

You can enlarge the photos, in the second one I outlined the area in question; if you look you can see the blue throttle body gasket.

That looks about normal......if you think it is leaking there, just spray some carb cleaner in the gap to see if there is a change in idle...

Did you replace the MAF? Aftermarket, or OEM rebuild?

Yes, I replaced it with a Dorman MAF.

What Tech 2 is telling you is the best way to search for vacuum leaks. I found a problem with my Dorman UIM by spraying WD40 where my manifold meets the throttle body. I would never by Dorman again as it had warped and degraded above the EGR stovepipe area. A better choice is ATP which can be found at Amazon for about $85.

There is nothing wrong with the new Dorman UIM Kits, they come with the reduced diameter EGR stove pipes, which fixes the old EGR issue you speak of.
You can pay a lot more for a UIM with the reduced diameter EGR stove pipe, as well as a steel bushing in the UIM part, but for as much more that you have to pay I did not seeing going that route worth it, so far 4 years later and no issues.