93 ATX lost power limp mode

Discussion in 'Gen 1 & 2 - Emergency Issues - Help & Maintenance' started by SHOTUNES, Jul 5, 2020.


    SHOTUNES Member

    Jul 22, 2004
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    Hello after driving car on hot day for 40 min mostly highway car started making rattling sound drivers side. After sitting 20 min started up fine drove 5 mi. and trying to get onto freeway car went into limp mode no acceleration barely get to 30. Slowly accelerating to 60 put on cruise and then tired to give some gas and she shut down oil light flickered could hear rattling sound engine stalled out towed home. Car was cooled down and would start to move into driveway but hear could hear that metal rattling tried to pull codes. looks like 111, 176, 177, 336, 542, 647. thanks for any help. ps she has not been driven for long time or far either has some oil leak that smokes when warmed up. possibly rear main seal leak has full oil also
  2. rubydist

    rubydist SHO Master Staff Member Super Moderators

    Jun 25, 2007
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    176 - lean left bank
    177 - rich left bank
    336 - dpfe sensor signal high
    542 - fuel pump always on/ bad ground
    647 - trans 3rd gear failure

    So the pcm is complaining of both rich and lean on the left / front bank - I would start with a new oxy sensor for that one, but it may have some other issue too - depends on how long its been since codes were reset.

    The dpfe sensor signal being high could be the sensor is bad but most often is related to clogged passages in the egr system. You can find a lot of threads about that here on the forum.

    The fuel pump code is set when the engine stalls for any reason and can be ignored.

    I have never seen any of the above-described codes result in limp mode.

    The transmission code is saying that 3rd gear is not engaging properly or slipping significantly. This can result in limp mode, and in every case I have seen, means you need a new transmission or full rebuild.
    luigisho and zoomlater like this.
  3. luigisho

    luigisho SHO Member

    Nov 2, 2001
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    va beach,va
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    Well if the tranny has to come out, at least the rear main seal will be easy to change.
    I agree with everything posted regarding codes. I would clean out the egr passages, clear the codes and run it around a little and see what pops back up. I have never seen a faulty transmission code not be an actual trans issue. That being said, these are really old, maybe you'll win the tranny lottery and it's the first one!

    I would also give the MAF sensor filament a good spray with electronics cleaner just for fun.
  4. BaySHO Performance

    BaySHO Performance SHO Member

    Feb 25, 2001
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    SF South Bay
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    Agreed, only the 647 would cause the engine to stumble, although the cause may not throw a code, such as a bad plug or wire, or a vacuum leak / dirty MAF. But none of those would cause the engine to rattle.

    If the transmission has to come out, by all means change the rear main seal, but it's unlikely to be the cause of the oil leak. I've never seen one fail in the last 250 cars / 20 years.

    If the leak is between the oil pan and transmission, the rear oil pan seal has failed. The factory puts the seals in dry. They eventually get rock hard, exposing a design flaw in the engine. Pic shows the front edge of the rear main seal carrier with the groove for the oil pan gasket. Notice that there's a small rectangular hole at the end of the groove. This is plugged with a tab on the gasket, but it eventually leaks from this point.

    Solution is to put a dab of gasket sealer on the block where the ends of both gaskets sit. Dielectric grease helps the gaskets stay in place during installation.

    PaulTAutoX, luigisho and zoomlater like this.

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