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Engine running rough

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Rich12, Jan 1, 2014.

  1. Rich12

    Rich12 Member

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    I decided to run a 2 tanks of E25 though my Gen 2 and now I've been noticing its running really rough at idle: no check engine codes, though. MPG is fine and I cant hear the clatter at speed or during acceleration. Sounds much worse than the usual ICE clatter. 110k and oils is fresh.

    Sounds like the engine has ball bearings going though it...best way to describe it.
     
    #1 Rich12, Jan 1, 2014
  2. uart

    uart Senior Member

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    Hi Rich. Some people describe the sound of pre-ignition (pinging) as a bit like marbles or ball bearings rattling in the heads. The strange thing here however is that pre-ignition is usually most noticeable under high load, particularly high load at lowish revs. So it might not be the problem, but it wouldn't hurt to try a tank of premium (higher octane) just to see if it has any effect.
     
    #2 uart, Jan 2, 2014
  3. salguod

    salguod Member

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    E25 as in 25% ethanol? Is it OK to run more than 10% ethanol in a Prius?

    Ethanol has a much higher octane rating than straight gas, I'd bet that E25 is higher than premium gas. Not likely a knock problem, but it is possible that it wouldn't run well on that much ethanol.
     
    #3 salguod, Jan 3, 2014
  4. Rich12

    Rich12 Member

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    Yeah it's 91 octane and 25% ethanol. It's still running rough even after a tank of regular. Any suggestions? Could this damage the engine?
     
    #4 Rich12, Jan 4, 2014
  5. bisco

    bisco cookie crumbler

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    hard to figure what damage could have been done. you might have to try a process of elimination, spark plugs, injectors, throttle body and etc.
     
    #5 bisco, Jan 4, 2014
  6. Rich12

    Rich12 Member

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    Thanks. Really.
     
    #6 Rich12, Jan 4, 2014
  7. edthefox5

    edthefox5 Senior Member

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    Why the 2 tanks of e25 anyway? Were you chasing an engine issue? Throw a code? Probably just needs a good throttle body & maf clean.
     
    #7 edthefox5, Jan 4, 2014
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