the truck: 02 F150 7700 4x4 5.4L

the problem: the truck starts fine but then idles low, almost shutting off then returns to normal idle, the truck also has a slight miss on acceleration

the question: are the two problems related? what is the cause?

I plan on changing the plugs in the near future but ive heard horror stories about plug blow outs. is there a way to check the plug coils to see if they are good, and is there a performance upgrade coil available?

 

Is the CEL on?

 

no CEL light

 

Anyone?

 

I'd try to get the codes read by a good scanner... Sometimes it takes a lot of misfires in a shorter time span for your truck to throw the light on... If the problem is intermittent then it will take forever or until the problem gets worse...

See if you have any pending codes without a CEL, sounds like you may have an intermittent coil problem...

Can you get it to miss on purpose? certain rpm and speed? If so make it miss here and there while driving, maybe you can get it to cough up a code... Took me a few days of forcing a miss at low RPMs at 40 to get a code before to find a bad coil...

Just a guess, could be a bad plug or injector as well, or many or both... You'll have to troubleshoot the problem out...

 

Id venture a bad coil. You can go to a dealership and get it diagnosed if there are no codes being thrown or wait it out till it does throw the code. Or depending on mileage on the vehicle replace all the cops and plugs.

 

it is a higher mileage truck, i'm planning to replace the plugs and i was hoping to upgrade the coils, so now my question is are there any options for a coil upgrade?

 

Eh, I'd stick with motorcraft, there are other options but I haven't heard anything good yet...

 

Global on ebay are great for the price about 80 bucks for the set as opposed to 50 for each one.