has anyone tried the speed chip for mustangs that they sell in ebay with the money back warranty? it seems to good to be true if you know about it let me know before i make a mistake buyin it
You mean the resistor "speed chip"? It's a scam. There have been threads on this before on stangnet.
The resistor fools the computer into thinking that the intake air is colder than it really is. The computer advances the timing a little (giving you a little more power), and it also adds more fuel, lowering your MPG and making the engine run rich. Eventually, the rich mixture will cause you a lot of problems and repairs.