My 99 F-150 XLT went into the shop the other day as it wasn't firing on one of it's cylinders. Ol' #4 was not working. Anyway, it turned out to be a bad #4 coil. The mechanic said it was a common problem among the 5.4 l. motors as the #4 coil is located right underneath the heater hose and it was somewhat common for the hoses to leak and take out the coil.

Just was curious if anyone else has had this happen to them...and also provide an FYI to anyone and everyone if their 5.4 starts running rough.

 

I've heard of the problem. Mine was leaking on my 4.6, but after smelling hot antifreeze, I traced the problem to the heater hose. The cheap factory hose clamp is the culprit, I put a good aftermark clamp on....problem fixed.

 

Happened to me too. At +-17,000 km's.

99 5.4 XLT

 

common problem..!!

 

Yep, do a search. You'r PC may crash trying to display all the results.