Okay, so i've got all my parts ordered to replace the isolator bolts.

So my plan (once it warms up) is to take the intake plenums off, replace the gaskets and the isolator bolts (clean/vacuum the egr ports while the intake is off) replace the bushings on the IMRC and verify the butterfly valves are clean and operate smoothly.

I'll probably also remove the fuel injectors and clean them, and install new o-rings, which I also ordered.

I would assume that if the PCV elbow would qualify as a vacuum leak, then valve cover gaskets would too, right? I ordered those to replace them while I am at it too.

Does all this sound like the right thing to do, or am I going overboard trying to rule things out? It just seems that if I've got everything removed anyway, that would be the time to do this sort of maintenance.

 

You may want to be careful with the IMRC, I don't think you are supposed to manually operate the butterflys. You may want to do some homework on that one, I have heard that you shouldn't move them. Perhaps someone else will chime in on that. The new bushings are a good idea though.

The valve cover gaskets "can" cause your lean codes, but it is very rare. If they are leaking oil then go for it. Or if it just makes you feel better, then have at it.

 

Thanks for the advice about the IMRC, I will look into it. I would think that operating the butterfly would be okay once the linkage was removed to replace the bushings. But I'll check.

The passenger side valve cover is pretty oily, but some of that could be from the PCV elbow grommet too. I guess I can pick those up at the auto parts store sometime... they're cheap. The drivers side is a little oily but that might be from me trying to hit the oil filler spout with a quart of oil. LOL

 

Ended up working on it this weekend.

replaced intake plenum gasket set (upper/middle)
replaced throttle gasket
replaced PCV (on throttle body) cuz o-ring was hard and baked
replaced valve cover gaskets w/ new bolt grommets
replaced middle plenum isolator bolts (8)
also removed fuel rail and injectors, cleaned w/carb cleaner and homemade spray setup, then replaced all o-rings
cleaned oily gunk from the orifaces of all 6 EGR ports and blew out EGR passages w/ compressed air

Started it up and it runs like a top. Normal idle (around 840 rpms) better SHRTFT's hover around 0% at idle and better front O2 readings (nice fluctuating wave .1 - .75 V at idle instead of a flatline .03 V at idle)

Thanks to all who posted. I'm no mechanic, but this was pretty easy stuff... and took maybe $150 in parts, rags, solvents and a few tools I didn't have before.

 

congrats! See I told you it wasn't that hard to do.