[pbanders]

OK, to start with, the AAR not closing will not cause the system to go rich..... so you don't have to worry about that.

First, I suggest looking at my web pages for diagnostic information. It's very hard to diagnose problems when I'm not certain if the owner has gone through a systematic analysis of their running problems. That said, here are a couple of comments.

Have you checked the compression and your idle vacuum level? You say the motor is old and smokes - maybe its got low compression, sticking valve, etc. Next, if you're sure this is an FI problem, you need to determine if this is a lean or rich condition problem. Generally, when a motor is very weak in performance, I'd suspect a lean condition. T4 motors love to run rich. Here, I'd check the head temp sensor at cold and hot, using values from my web page for normal responses.