Truck is running rough at different speeds, I think it is depended on RPM and load. No CEL yet, but i did notice the Theft light blinks but not at a steady rate. Seems it blinks more when the engine is running rough.

Any ideas on this one?

Thanks

 

specs on vehicle please

 

2001 F150 SC 4.6L 4x4 Auto

 

i have seen some funky stuff happening if a coil shorts out. it can cause all kinds of backfeeding, electrical interference, you name it. whenever your truck skips, if it is a coil pack going out, it probably making the processor go stupid, causing the theft light to blink.

 

Thanks, I did just change the plugs as one had been getting wet and formed corrision on the plug causing a misfire on #8. maybe the coil is also going bad. I will see if the CEL comes on and give me a clue.

 

it may not come on