I have a 2001 ford f150 5.4L V8. I am having trouble finding a miss in the engine while under a mild load. I replaced the plugs and by process of elimination went through to each coil and swapped out them with a new one. Still have a miss. I had this problem 3 other times before and this worked but this time it did not. Could it be someting else like a sensor? No engine light is on to have trouble code read. Also any ideas why this keeps happening? No moisture is ever present around any plug. I am also getting a whistling noise at 3000 rpms and up inside the cab behind the dash any ideas? No, im not selling my truck. I like it.
have the same problem?
Wednesday, December 17th, 2008 AT 10:19 PM
If your getting a misfire it should be setting the MIL on. If it's intermittent the codes will be stored as pending and will not bring the light on constantly. Have the car read for codes. See if there are any intermittent pending codes stored? Most good autoparts stores will read the codes for free?
Thursday, December 18th, 2008 AT 9:04 AM
You would think an engine light would come on but it did not. This has happened three other times and no engine light. What I did find today is that one coil tested poorly on the secondary side caused by corrosion around the contact/inner spring inside the plug boot. Also found a cracked plug insulator on a different cylinder. This plug was a brand new motorcraft. All this and no engine light go figure. An ohm meter test told the tale on the coil. Should be.55 on primary and 5500 on the secondary. Erratic meter readings means bad coil. Testing this at home is quite a job since accessibility to the coils is very limited, along with the plugs. But alittle patience its not to bad. My advice to anyone reading this is if you change coils change plugs also. Inspect each very closely. Use a ohm meter when coil is removed this will save time and money. I learned something all four times this has happened.