Just got this targeted email from Amazon and Chase, YMMV:
ACTIVATE NOW AND EARN A TOTAL OF 4% BACK AT GAS STATIONS
from Sept. 1 through Nov. 30, 2017.
Rewards add up fast when you earn 4% Back at gas stations with your Amazon Rewards Visa Signature Card between September 1 – November 30, 2017.
on to www.mychasebonus.com/4BACK
footnote* Earn an extra 2% Back (for a total of 4%) on gas purchases: During the promotional period earn a total of 4% Back per $1 spent at gas stations when you use your Amazon Rewards Visa Signature credit card. That's an extra 2% Back in addition to the 2% Back you already earn on purchases at gas stations. To be eligible for this offer, cardmembers who received this offer directly from Chase must log on to www.mychasebonus.com/4BACK
or click the Activate Now button and enroll by 09/30/17, 11:59 p.m. EST. The % Back earned for this promotion will post to your account as bonus points during the applicable monthly billing cycle and are generally available to be used at the beginning of the next billing cycle; bonus points earned on purchases made near the end of a billing cycle may take up to one additional billing cycle to become available. To qualify for this promotional offer, your account must be open and not in default at the time of fulfillment. This promotional offer is non-transferable. For more information about your rewards program,