This is typical of early GM fuel injectors (multec-1). On the 2.8L, 3.1L and 3.3L group fired systems, one shorted injector will cause a no start! On the sequential engines, like on this Cadillac, misfiring and rough idle is the typical complaint. Be aware of replacement parts and the characteristic differences you will see in a current ramp waveform. For you scope guys out there, this type of thing can have you barking up the wrong tree.
Rough idle, MAP code 33, intermittent no start (shorted injectors) – GM
How to test for shorted fuel injectors (1987-1994 GM Cars)
How to interpret fuel injector waveforms (a ScannerDanner Premium video)
GM 3300 Intermittent no start rough idle (shorted injectors) part 2
For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available at www.scannerdanner.com as an eBook or paper book.
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