Hi Guys,
Thanks for the responses. I haven't had a chance to work on it until today.
I don't have a fuel pressure gauge, so I started by capping off all vacuum lines except FPR and MAP. Then I hooked them back up one by one and found that the line going to the PCV is the culprit. How critical is the PCV? Is it ok to leave that line with no vacuum? I can't tell if it's just one cylinder or not, because I have to be driving it to make it happen. I haven't checked compression either. It's been probably 5 years since I took all the AIR injection junk off.

 

When you say the PCV line was the culprit, what exactly do you mean by that?

Regardless, it's "okay" to leave the crankcase line open to atmosphere, although when you do that you really should leave the valve cover vent open to atmosphere as well. i.e. you either want them both open or both closed (preferably the later).

Any way, fill us in on what you did and what you actually determined and we'll go from there.

 

Basically when I disconnected the line going to the PCV and capped the branch on the vacuum tree, my idle dropped by 100 or so RPMs. None of the other lines made a difference. I took it for a quick test drive, but it wasn't long enough to see if it actually made a difference in the exhaust temps. Eventually, I plan to replace the PCV valve and seal in the valve cover. Hopefully then I'll be able to reconnect the line to vacuum.