Incongruent distractor-target pairs evoke response conflict as indicated by prolonged reaction times and a fronto-central N2 ERP component. Experimental blocks with predominantly congruent trials even yield larger behavioral congruency effects (i.e., proportion congruency effect). Recently, Jost and colleagues (2022) reported a strikingly large, but very consistent N2 congruency effect in a temporal flanker task (essentially a priming paradigm) that was modulated by proportion congruency – a finding that is in contrast to the majority of flanker task studies that failed to yield this effect. Here, we re-examined this finding in another lab with n = 32 new participants and a variation of proportion congruency across three levels (25%, 50%, or 75% congruent trials in a block). Our results confirmed the hypothesized two-way interaction: Congruency effects in the fronto-central N2 varied across the proportion congruency levels, arguably reflecting the degree of cognitive effort required to resolve the response conflict. This assumption is further corroborated by analyses of lateralized-readiness potentials (LRPs), which revealed more distractor-induced response activation under high congruency conditions. Interestingly, congruency effects were not only evident in the N2 component but likewise in a temporally preceding positive peak. Upon closer inspection, the ERP pattern resembles an oscillation on the order of about 7Hz, suggesting that the N2 component at least partially reflects a theta band oscillatory process of the mPFC/ACC. In conclusion, the temporal flanker task in combination with a proportion congruency manipulation consistently evokes target-related N2 congruency effects. Quantifying theta oscillations might be a reasonable avenue for future research.