This paper reports on an acoustic investigation of inter-consonantal intervals in plosive sequences in Tripolitanian Libyan Arabic (TLA). TLA permits a wide range of two, three, and four-consonant strings within and across word boundaries. Previous descriptive work has suggested that TLA is characterized by widespread, partly optional vowel epenthesis throughout these sequences. We conducted a production study to investigate the phonetic and phonological properties of inter-consonantal intervals (ICIs) in these sequences, including their durations and voicing characteristics, as well as the voicing of surrounding plosive hold phases. Our aim was to assess the extent of ‘variable epenthesis’ and narrow down the range of possible accounts for it. Unlike many previous studies, we did not rely on native speaker intuitions and made minimal use of manual categorical coding, instead focusing on modelling distributions of continuous acoustic parameters. The central question we address is whether our data contain patterns that can only be explained with reference to phonological vowel insertion—given that variable epenthesis can also be accounted for in terms of vocoid intrusion alone (Hall, 2006). Our study improves our understanding of consonant articulations in Arabic, and of epenthesis and related phenomena.