Diagnosing a Rough Idle/Running Rich Condition

[alansb1982]

Hi guys,

1994 Mazda B2300 2.3L Manual Transmission. I've got a rough idle that smells rich from the exhaust. It doesn't ever stall out, and it doesn't seem to run rough under acceleration. From what I can gather through research, some possibilities are a vacuum leak, a bad IAC valve, and/or a bad MAF sensor. I'm sure there are other possibilities that I don't know about. Forgive my inexperience; I picked up this ride in part because I wanted to learn how to work on cars.

Could anybody give me a run down of how they would go about diagnosing this issue, starting with the least laborious/expensive and ending with the most?

 

[alansb1982]

Also, I'm wondering if another issue I'm having with the car might be related to this. Lately, when I try to crank the engine on the first try (warm or cold), the starter solenoid "knocks" once, but doesn't crank. On the second try, the car starts right up. Based on some research, it appears that it could be bad/corroded battery cables and/or connections to the terminals.

The negative terminal had so much corrosion on it that, when I tried to disconnected, the bolt broke in two. I cleaned up the cable end and terminal, and replaced the bolt, but not the cable.

So here's the question: Could these two problems be interrelated? As in, could a bad battery connection cause the solenoid issue AND ALSO cause a bad spark issue which would in turn cause a rough idle/rich condition issue?