How troubleshoot ignition exchange computer fault?

I don't think there is a BCM for those year
why do you want to change BCM (body computer module)
differ from PCM (powertrain control module)

Get a second ignition key, the one you are using is dirty or moisted, you need to turn on and off the car witha clean key, hapens to me once in a while.!!

the 1993 chevy caprice had a 5.7 engine with distributor in which you need to adjust ignition timing with a timing light.the 1994 - 1996 vechicle timing controlled by pcm, your problem does sound like timing off.

have you recently changed wheels or tire size? that is a definite change to speed. it changes everything about speed,stopping distance,control of car,handling conditions,when you go up to 18in or 20in 22in 24in rims or tires it changes the whole handling of the car. maybe you bought it that way,look at tire size,your car should come from factory with 15inch rims and tires max. any changes to that increases the speed.thank you for choosing fixya.com

1994 Chevrolet Caprice Classic could be OBD I

Reading OBD 1 Codes on GM 1982 1995

There is no digital display for ODB I ...the check engine light will blink a series of flashes to provide a code for the fault. Check the link for the video that explains how to retrieve fault codes.

your resistor chip on your VATS key make look fine but there are also contacts just inside your key way on your ignition that work with your key to make the connection to the cars computer allowing it to read the resistors value and if it matches, allows to car to start, if it does not make proper contact some time, it will not read the key and car will not start, probably you need to have the ignition replaced.......

Only thing you can do yourself is to pull off the connector on the computer and check pins for corrosion. If you can get another computer on "loan" you might try plugging it in. though its somewhat rare (it should be) computers do fail. On older cars you can likely get a replacement in any scrap yard. sorry I can't help more, but with no readings, everything points to what I've said. You should also check ignition switch to amke sure power is coming out of there to remainder of system.

WELL I HAD THE SAME PROB. ON A 95 CHEVY CAPRICE.I REMOVED THE IGNITION AND THE WIRE WAS BROKE.WHEN U TURN THE KEY THE PASS KEY WIRE TURNS WITH THE IGNITION,WHAT A FAULTY DESIGN.ANY HOW BUY A NEW IGNITION AND KEY THAT SHOULD SOLVE THE PROB. GOOD LUCK

didnt get water in the air intake right ?

Ignition module. They get hot and shut down. After they cool they work again.