I ordered two gallons of Neutra 131 from Tim Mills on Tuesday and got them on Friday. I am going to run this in the engine oil and the fuel tank. I already ran Auto-RX three times in my motor. 1996 Ford F-150 302 V-8 (253,000) miles now on it. I always ran Motorcraft 15-40 from 100,000 miles until now. I am switching to Mobil Devlac 1300 15-40 conventional oil until this motor dies. Hopefully the three Auto-RX treatments got the motor very clean and the Neutra 131 will get anything the Auto-RX missed.