2001 Ford Escape XLT P0171 and P0174 Codes: Idle Issues After Purchase
I recently purchased a 2001 Ford Escape XLT 'as is' last night. When I handed over the payment, there was no check engine light on. However, exactly two hours later, the check engine light activated unexpectedly. At AutoZone, they ran a diagnostic and found two trouble codes: P0171 (Rich Mix Bank 1) and P0174 (Rich Mix Bank 2). These codes are related to fuel mixture issues in the engine. Today, I noticed a significant idle problem — when I put the vehicle into park after driving about 45 minutes, the engine would rev up unexpectedly, as if I had stepped on the gas. This behavior occurred twice during my round trip: once going to my destination and again returning home. It did not happen during a very short drive later. I'm concerned whether these symptoms are directly linked to the P0171 and P0174 codes, or if there's another underlying issue. Given that I just bought the car, I want to understand what could be causing this behavior and how much it might cost to fix. Any insights or suggestions would be greatly appreciated. Thanks in advance.
Review the official trouble code explanations for P0171 and P0176 in this forum to understand potential causes. While some issues can be addressed through DIY repairs, a professional diagnosis may be necessary. In the best-case scenario, a repair could cost around $200–$300 to diagnose and fix both the idle issue and the fuel mixture errors. This includes checking sensors, vacuum lines, and potential engine component wear.