Ok, so i went out in my 99 F150 4.6L today to get some 1/4 miles times with my edge evo and i am getting close to 19 seconds?!?! i have a programmer, exhaust and cold air intake; im pretty sure that is a high time even for a stock truck.
I know this part is not normal, but half way through the 1/4 mile my check-engine-soon light will start blinking, meaning random miss-fire, its killing me trying to figure out what is causing the problem.... *note:just replaced spark plugs like 3000 miles ago

Thanks,
Charles

 

What kind of sparkplugs did you use?

 

Do you hear of feel it miss-firing?

 

Are you 115% you installed the plugs correctly. Cause I taught I did after my spark plug change and it turned I had 2 wrong.

 

i think i got the iridium ones , and im pretty sure i did em right unless theres some trick of something and i can feel them misfire

 

Bump????

 

theres part of your problem these truck dont seem to like anything but motocraft sparkplugs

 

before i got them it was misfiring ten times worse, but i just took the ones that the napa auto guy told me were right so i dont know.

 

time to start checking the secondary parts of the ignition - wires, coils, etc. Misfire's are bad for the engine so the sooner the better. If you can't find anything yourself I'd suggest taking it in to someone

 

19 seconds is wayyy off for your truck. that or your programmer is fkn something up with the ecu.