It wasn't another $30

When last we tried, we thought a $30 Ignition Control Module (ICM) might do the trick in correcting the stumble in the A8.

Nope. 

My current line of thought is to look for vacuum leaks in the steam-punk engine ventilation hoses or to replace the air-flow sensor that helps the computer govern the mixture of fuel and spark.

On the one hand, much of the vacuum tubing has, to its credit, lasted for almost two decades and shouldn't be blamed for a minor leak. I've replaced one or two, but there are a few other pieces of original equipment.

On the other hand, the air flow sensor is triggering engine codes for "low readings."

Then again, detecting vacuum tube leaks can be done with a smoke-box (or, if I had Michael Phelps' lungs, a cigar), a propane bottle or, in a risky manner, with snap start.  Either push smoke into the hoses and watch where it leaks out, or hover some un-lit propane or snap-start around various points of a running engine and see if it gets sucked in and revs up the engine.  What woudl I do with a smoke box after this one use?  Is it worth another $40?

Of course, a replacement air flow sensor is $150, and may not be the issue.  I could go cheap, but is this the kind of senor you buy used from a scrap yard?

Ugh.

She runs.  She needs to go another year.  I'm trying to save up for her replacement.