Rough idle and no throttle response on cool mornings

Lincoln LS

  1. jberbrich

    jberbrich LVC Member

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    OK 2003 LS V8 experts. Here’s one for ya. I still enjoy driving mine, except first start in the mornings when the outside temps are below 60 degrees. Here are the symptoms. With cool morning temps, she starts right up, goes to 1500 rpm for about 20 seconds, then the idle slides down to a very rough idle less than 500 rpm and below. There is absolutely no throttle response and it would eventually stall, unless I immediately put the car in gear and punch the throttle, upon which I gain throttle response, and the car runs as designed for the rest of the day. I get no codes. I have cleaned the throttle body twice in the past 8 months with Seafoam spray and cleaned the MAF twice with MAF cleaner, which seems to maybe produce only a slight and short-lived improvement. The car has 175000 miles and I have maintained it faithfully with timely fluid changes, coil and spark plug changes, etc. The last coil and plug changes were about a year ago. I was thinking about replacing the throttle position sensor, since it seems pretty easy to access. Would I be wasting my time and money? Any other brighter ideas? Thanks brothers.
     
  2. jberbrich

    jberbrich LVC Member

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    Is LVC still alive and well? I have not received a single response on the above issue. Hey Joe, are you still out there to share your expertise?
     
  3. joegr

    joegr Dedicated LVC Member

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    I'm here, but I don't think I have anything useful to say yet. Your description does make the TPS plausible, but I would have expected an ETC failsafe error if that were it.

    Maybe monitor live sensor values (including TPS) while it is doing this and see if anything sticks out?
     
  4. AmsterDutch

    AmsterDutch Dedicated LVC Member

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    Do what Joe said but you may need to check the transmission relay; sounds like the transmission and engine do not communicate properly; also, has the ignition control module been checked or replaced? When did you change the Fuel filter last?
     
  5. AmsterDutch

    AmsterDutch Dedicated LVC Member

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    Is there a Throttle Control valve on the 2 Gen? or is that what the TPS represents?
     
  6. joegr

    joegr Dedicated LVC Member

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    Transmission relay???

    I assume you are asking if there is an IAC? There is not, the since the main (only) throttle valve is controlled electronically (ETC), it is used for engine idle control.
     
  7. jberbrich

    jberbrich LVC Member

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    Thanks Joe. Looks like I will have to take it to the dealer for analysis.
     
  8. jberbrich

    jberbrich LVC Member

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    I changed the fuel filter about a year ago. My transmission was shifting very firmly (thump) into reverse and from 3rd to 4th. I changed the soleoid pack, but no change. I then replaced about 3 quarts of transmission fluid with Lucas Transmission Fix to thicken up the fluid to see if these particular servo bores were worn. The shifting smoothed out considerably, pretty much confirming worn servo bores. No sensors have ever been changed on this vehicle, other than O2 sensors and several cleanings of the MAF. I guess after 175,000 miles, it is due for a thorough sensor check.
     
    Last edited: Nov 1, 2018
  9. clubairth

    clubairth Active LVC Member

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    I would still check for codes even if you don't have a check engine light. Then clear everything and make it run rough like you described.

    Maybe some kind of pending code might be hanging?
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  10. jberbrich

    jberbrich LVC Member

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    Roger Wilco. Thanks.
     
  11. Diesel980

    Diesel980 New LVC Member

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    EGR Valve leaking. Runs fine when warm right.
     
  12. joegr

    joegr Dedicated LVC Member

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    There is monitoring for that. It would throw a DTC for excess EGR flow. If the DPFE wasn't working correctly, there would be a DTC for insufficient EGR flow.
     
  13. Diesel980

    Diesel980 New LVC Member

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    I had the same issue in the past with a 04 la v 6 no codes or anything. Ran like a dog when cold. Replaced EGR Valve with a Motorcraft brand. Ran great. It would rob like crap on very cold mornings 25 degrees or colder
     

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