Owning a car is mostly about the small stuff until it is not. When your engine starts to stutter or lose power, it is usually the fuel injectors telling you they have had enough. This is not a repair you can ignore if you want to keep the car on the road. Most shops charge around $900 for a full set and the labor to swap them out.
Repair costs are usually firm, but you can find better labor rates during the mid-week slump when shops are less busy. Since this is not an optional upgrade, we need to focus on how to cover the bill without draining your savings in one go.
The 18-month window is a strict deadline, not a gift. If you still have a balance when the period ends, the standard interest rate will apply to whatever is left, making the repair much more expensive.