Ignition control module???

[89Laredo]

Almost sounds like your iac is acting up... it can get sticky, soak it in carb cleaner and spray it out good with air.

There is a vacuum activated shutter on the "snout" of the airbox.

The intake/exhaust bolts can loosen over time and cause an intermittent leak before they get real bad.

The coil/icm are potted and solid state, they almost never go bad. Cleaning the contacts isn't a bad idea.

[Infidel Edition]

Thanks for the input. It gives me direction

Cleaning is free (or close to free)
...so is checking bolts to make sure they're tight.

I'll try that first and see what she does.