2001 Ranger 4x4 4.0 acceleration issues

Discussion in 'Maintenance Shop' started by Bobs85gt, Nov 2, 2017.

  1. Bobs85gt

    Bobs85gt New Member

    I am looking at a Ranger that does not seem to want to accelerate beyond about 25mph. The owner lost the original key and had a locksmith create and program a new key. The truck starts and runs but it falls flat on it's face at about 25 and the theft light flashes. Any ideas? or should I just walk away from it?

    Thanks, Bob
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  3. mhoward

    mhoward Member

    You didn't specify the year of the truck, but you say a locksmith cut and PROGRAMMED a new key. I am assuming the truck is 1999+ and ran fine prior to losing the key? If the truck is 1999+ it means it has PATS (Passive Anti Theft System). When a key is NOT programmed correctly, the engine will crank, but won't start. I don't know of any instance where there is an exception to this rule. The flashing theft light gives me reason to think there is something wrong with the key programming. But the fact it will run up to 25 mph makes me think there is something else going on here. Have you put a scanner on it yet? Does it sound "funny" when you accelerate? I worked on a car back in the mid 1970's that wouldn't go over 30 mph or so. Turned out that the header "Y" pipe had collapsed internally (twin wall pipe). So this instance could possibly be a plugged cat or muffler. I would have someone try to rev the RPMs up to about 2000 and see if you are getting the expected exhaust out the back. If not, drop the exhaust off at the manifolds and see if that makes a difference. Without more info on the vehicle, it is hard to try to pin it down.
  4. OP

    Bobs85gt New Member

    It is a 2001 it has the 4.0 and auto. They said it ran fine prior to the key issue. I have not driven myself yet so I can only go with what I was told. It acts like it is not receiving fuel to accelerate. The battery was clear flat and they jump started it. I am starting to think it is actually a low voltage situation. I am going to swap good battery in it to test. I hate to"fix" before I make an offer on it though.
  5. mhoward

    mhoward Member

    Low voltage might be a possibility. Didn't think of that, so you may be on to something. Easy enough to test with a known good battery. You might check the fuel pressure at the rail to ensure it isn't a fuel pump issue. Back to the key thing for just a minute: Ford requires the programming of TWO keys when you are starting out with none. Did this locksmith cut and program two keys? Good luck and let me know what you find out.
  6. OP

    Bobs85gt New Member

    Well I made them a I really don't want it offer of $75 which they took. I swapped out the battery, which O'Reillys replaced under warranty. It fired up, warmed up, and I drove it 20 miles home. I found the door closed switch was bad and the dome light was running the battery down. So far I haven't found anything else going on with it. Going to change the oil and drive it till it falls apart
    Only has 87k miles so it may run a while as a 4x4 snow truck.
  7. mhoward

    mhoward Member

    Well! Can't beat that! A $75 Ranger... wish I could cop a deal like that! Congratulations! :)

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