The engine light was on before I replaced the coil pack. And the coil pack is a Motorcraft straight from the Ford dealership. I've thought it's a fuel injection problem somehwhere. I've thought about replacing the TPS sensor and checking to see if one of the injectors might be bad or something. In my opinion you'll be driving down the road and if you take your foot off the gas and just like idle down the road it's fine runs great and everything. But when you resume throttle it's jerks and vibrates and everything and lost all kinds of power going up hills. Does anybody have any clue what could be this problem?