04 hemi 5.7 runs good above 2k won't idle below 1k and runs rough, had some codes but I addressed as follows, open circuit cylinder 4, replaced injector, mis fire cylinder 8 changed plugs and coil pack, lean both banks replaced map
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The generic basics for a rough idle on any vehicle is to check for a leak of some kind, fuel--egr--vacuum leak, something of that nature. I'm not sure why you replaced the tps, unless you got a code of some kind? The code doesn't tell you what to replace. With any electrical sensor, I'd want to check wiring circuits, first, before replacing.
Clean the throttle body and idle air system, see if it helps. Your saying it runs good, off idle?
Have you changed your fuel filter? When is the last time you changed your sparkplugs? Have you had any codes on the computer? Heres what I would do. First change your sparkplugs. This is a 4-6 hour job. You have to unbolt the cop(coil on plug assembly). After you change the plugs your truck will run rough. Drive it around the block then back to your house. It will take 3-5 restarts before your truck quits running rough. Reason for this is because your computer is trying to "relearn" the firing order. I have done this several times so i know what i am talking about. You can even look it up. Your 2000 expedition is a dang good truck with a great engine. After your computer relearns the firing order then the rough idle will be gone. Then I would take it out on the freeway and run it hard for 5-10 miles. If you experience a miss or two then that means you need a new cop(s). Get a code reader and it will tell you which cop is bad. Cops are expensive. I bought 6 new ones on ebay for $40. If you buy from autozone or ford dealer then you are looking at about 80-100 bucks a piece. Tell me if this helps. Ford makes a good truck and the expedition is a great truck. Mine is a 2000 expedition also. I have 248,000 miles on it and running strong with no burning oil. Good luck.
Check engine compression and compare. then test running engine compression most engines have about 130-170 cranking compression and about 90-110 running compression. OR bring that cylinder to its Top Dead Center compression stroke apply air to the cylinder and check to see where the air is going open throttle plate bad intake valve, from exhaust pipe bad exhaust valve, from oil cap piston rings.
YOU COULD BE HAVING ENGINE MISFIRE.DUE TO BAD SPARK PLUGS AND WIRES.ALSO DIRTY FUEL INJECTORS WILL CAUSE ENGINE TO ROUGH IDLE OR IDLE UP AND DOWN.PUT A BOTTLE OF FUEL INJECTOR CLEAN IN A FULL TANK OF GAS.ALSO CHANGE PLUGS AND WIRES.IF TRUCK HAS 30000 TO 60000 MILES ON IT.THATS THE SCHEDULE MAINTENCE INTERVALS IF SPARK PLUGS HAS NOT BEEN CHANGED.
IF YOU GOT CYLINDER MISFIRE.OR OPEN FUEL INJECTOR.THAT WILL CAUSE THE PCM TO ENRICHEN FUEL MIXTURE.TO ADJUST TO DEAD CYLINDER.WHICH ACT AS A LARGE VACUUM LEAK.THATS WHY YOUR EXHAUST TAIL PIPES HAS A RAW FUEL SMELL AND WHITE SMOKES.
Check the voltage of battery with voltmeter.. It is sometimes possible that if voltage of battery drops and jump start is needed, your computer will only charge to the last voltage that was recognized which would be when jumped...Try and charge the battery if possible I would actually suggest that you have your battery tested at local auto parts store and if it is presumed in good condition ,let them charge for you to max capacity . If battery has been tested and labeled as no good replace if necessary... Oh, and first thing you should do is make sure your positive and negative battery connections are clean and tight...if this didnt fix problem please give more info on what was found when advice above was followed...Good Luck!!!!