I've been doing a lot of injector research lately, and just ordered 6 of the Motorwest injectors. I found the info below on their site....apparently even a new or rebuilt "brown" injector can have this design flaw? Just FYI to anyone struggling with misfires/ thinking about replacing/ rebuilding injectors....
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After years of research and development, we are discontinuing this product and introducing and more reliable and cost effective Denso injector replacement.The original 23250-62040 (brown) injectors have an internal solenoid defect that fails over time, with high mileage engines being the most affected by this.
The symptoms begin as an intermittent random misfire. The issue then becomes ongoing when the vehicle reaches normal operating temperature. Finally the internal injector solenoid dies and the misfire becomes permanent.
The great news is we now offer a solution to solve the issue permanently. We are so confident in the replacement injector’s reliability that we are offering Lifetime Warranty on every unit sold!
The Denso replacements can be found by clicking here, or searching our store for part number HP831.
Link:
Denso Fuel Injector Replacement Set for 3.4L V6 4Runner Tacoma and Tundra - HP831 (Naturally Aspirated 5VZ-FE only) | MotorWest Performance