I bought a used 2003 F150 with 100,000 miles and a Triton 5.4L. After a month the engine started idling rough and is making popping sound that are synchronise to the engine RPM. If you throttle the engine up the popping increases. Need help on what I should be checking and where to look.
Thanks..

I had a loose spark plug did same thing.Sounds like a lotta work but i was gonna trade my truck it bugged me so bad.

Could be a blown out spark plug and yes this is a common problem with the 4.6,5.4 and 6.8 triton engines also pulling the threads out.Removal of the cylinder head does not to be done,there is a special tool kit to fix this.Minus well change the rest of the plugs too at the same time.Ford garages charge $300.00 a hole to put in an insert .

Thanks.. Was this a defect in the design of the engine or is this a common problem?
Pat53

THIS MAY HELP , FORD (TSB 05-22-8) , DESCRIPTION: WDS COP KIT DIAGNOSTIC TIPS - COIL ON PLUG (COP) IGNITION SYSTEMS - ENGINE MISFIRE OR ROUGH RUNNING , ACTION: The misfiring cylinder must be identified through Self-Test misfire codes or through WDS Power Balance. Rule out base engine problems, rule out fuel problems, and then look at ignition problems (be sure to rule out coil primary circuit issues). Once the above steps have been completed, and the issue is in the secondary part of the ignition system, the oscilloscope procedure outlined in this TSB can isolate the difference between a coil or spark plug problem.

ANOTHER TSB 05-4-17 (http://www.fordtechservice.dealerconnection.com/renderers/tsb_frames.asp?leftside=/pubs/content/~WT/~MUS~LEN/3619/tsb05-04-17.htm&market=US&lang=EN) :INTERMITTENT ROUGH IDLE - NON-COMMANDED EGR FLOW
ISSUE: Some 1997-2005 5.4L 2V vehicles may exhibit an intermittent rough idle. This may be due to non-commanded EGR flow.

HOPE THIS HELPS

It is a very common problem with the spark plugs blowing out on the 4.6,5.4 and 6.8 triton engines.Snap On does make the repair kit for this and does not give it away,$300.00 for it.