It was a matter of time before Iran figured out actual annoyances to the US. Blowing up oil and gas facilities hurts the US the least. In fact energy disruption for the EU and China and weakening of the Gulf monarchies (which had pesky BRICS ambitions in the past) may be exactly what the US wants.

For maximum annoyance Iran should let through EU and Chinese tankers but block US and Israeli tankers. This would infuriate Trump to no end.

That would just render the blockade entirely pointless.

Prices are going up in the US because oil is a global market, not because that specific oil would actually have been delivered to the US.