My 04 f150 had a rough idle and would sometimes stall out. dealer said it was throttle body so I replaced. The idle is still rough but it it doesn't stall. Could it be a coil pack? if so do I need to replace all of them or just find the one that could be bad?

I have a 2005 f150,with a 4.6 and it idles rough and when you turn on the ac it wants to die. Checked the codes and there are no codes.Any suggestions?

Clean the maf sensor with electronis cleaner. check the fuel pressure. clean the idle air control valve. this requires removal of the unit and you will need a gasket when replacing. check the throtle position sensor for proper specification. check spark plugs and wires. replace if it's been a long time since the last tune up. check pcv. clean the egr valve. a haynes or chilton repair manual will help out a great deal with these procedures. they cost around $15-$20

Is the rough idle a miss or a rough idle? check the EGR valve if this is stuck open it will cause a rough idle and also cause the engine to die.you should be able to remove the vacuum line. if your idle changes Check the EGR control valve. valve may be holding EGR valve open all of the time causing problem. if removing vacuum hose from the EGR valve doesn't change anything remove the EGR valve to see if it is functioning clean it thoroughly with carb cleaner. you may have to remove the throttle body to get to the other side of the EGR port to clean the carbon build up out.

Sounds similar to my problem. Diagnostics said coils bad, O2 sensor sticking, MAS needed cleaning. Turned out to be a leaking vacuum line. Mine was the one from the PCV.

Sounds more lik carbon deposites, get a can of injector cleaner and it will probably fix