92 GMC Jimmy throwing a "running rich" code

I have a 1992 GMC Jimmy V-6 Vortec with over 181,000 miles. Recently I began having problems with my car sputtering during acceleration and then clearing as my car gains speed. During these episodes, the engine idles roughly and at times "bucks" slightly while driving. My check engine light came on and I took it to a mechanic who said that my car was "running rich" and believes it was my fuel injection "spider" leaking. I took it to another mechanic for a second opinion and he told me that he didn't think it was the spider because I was not "misfiring". Upon his recommendation, I spoke with a mechanic at a GMC dealership who stated he believed the first mechanic may be right, but it could also be the fuel line (or a plastic line). Either way, he says the only way to tell is to take the intake off and look.

Regardless of my mode of action, it looks like this will be a pretty costly project. What I don't want to do is pay the money only to find that my "spider" isn't the problem. Any other questions that I should ask the mechanic to try to pinpoint the problem or any other alternatives? Also, if I do fix this, is there anything I should replace while I'm doing this? I would love to hear any thoughts on this issue.