Truck idles fine and runs great when cold. When the truck warms up it begins to run rough almost cuts off the engine when running down the road.
Does it run rough at hot idle ? How many miles ? Any recent work done on engine ?
Yes at hot idle still cuts out. It has approx 140000 and I have already replaced plugs wires cap rotor and fuel pump going to replace the oxygen sensor this weekend
I replaced the fuel pumps and fuel selector switch and temp sensor still have the same issue
Is the EGR hanging open ?
Not sure I will have to take a part and check that next
You may be able to feel with your finger if the diaphragm will move up and down and see if the idle worsens or gets better. The IAC idle air control may need cleaning to let enough air flow for it to idle smoothly. Also, an O2 sensor stuck on high/rich could be making it run too rich after warm up.
If there are no codes, keep in mind that early 90's ford EEC IV units (Electronic Engine Control) units are known to have problems the older they get. Not sure if your model has an EEC-IV but if you have replaced about everything else in the ignition system keep that in mind. Research "ford eec 460 module problem" or similar. I had random misses at idle and under load. Turned out to be leaking capacitors on the circuit board inside the EEC module.
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SOURCE: 2000 Ford Explorerer rough idle When cold
what codes are present? If it is lean codes P0171/P0174 problem is most likely the orings leaking between upper and lower intake manifold if this is a 4.0L
SOURCE: rough idle after warm up
I'd take a look at the temp sender...the engines computer may be
"thinking" the engine is still cold when it's not. That would cause it
run rich (and rough) after it's warmed up. Generally the sender can be
tested with an ordinary volt/ohmeter but you will need the
specifications available in most inexpensive manuals. As with any
complicated electronics system, I can only give you my best guess,
without the luxury of doing any hands-on testing myself.
Good Luck!!
SOURCE: 1991 corvette-engine runs rough then cuts off
could be vapor locking, losen up the fuel cap and see if that helps if so then replace it!!!!!!
and chane the fuel filter also
SOURCE: car idles and runs rough intermittently after engne is warm.
one of you air line pipes could have collapsed or split which will cause a problem with idling and performance and it will give no smoke signs
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