Seafoam full can in the tank, now runs bad. Can this be fixed. how?

Discussion in 'Gen 2 Prius Main Forum' started by monoshock, Mar 24, 2026 at 8:14 PM.

  1. monoshock

    monoshock Member

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    Well I've used seafoam for many years with no problems. However I forgot and dumped a whole can in my 2004. Now it runs weird. 210k miles. How can I fix my mistake?
     
    #1 monoshock, Mar 24, 2026 at 8:14 PM
  2. dolj

    dolj Senior Member

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    Define weird.
     
    #2 dolj, Mar 24, 2026 at 9:35 PM
  3. ChapmanF

    ChapmanF Senior Member

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    That'll fix it?
     
    #3 ChapmanF, Mar 24, 2026 at 9:45 PM
  4. PriusCamper

    PriusCamper Senior Member

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    How many gallons was it mixed in with/how full was tank? How many gallons have you added and how many miles since whatever "weird" means started?

    Also when was last time you replaced plugs and cleaned throttle body and MAF sensor?
     
    #4 PriusCamper, Mar 24, 2026 at 10:51 PM
  5. monoshock

    monoshock Member

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    The tank was full. Around 200 miles is when the problems started, before the car ran great. i connected two different scanners and both show catalytic problems but with no codes. Hope the catalytic isn't clogged from carbon being broken loose from the seafoam. I'll post a picture of the scanner.
     
    #5 monoshock, Mar 25, 2026 at 6:40 AM
  6. pasadena_commut

    pasadena_commut Senior Member

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    How does a scanner show a catalytic problem but no code???
     
    #6 pasadena_commut, Mar 25, 2026 at 3:27 PM
    Brian1954 likes this.
  7. PriusCamper

    PriusCamper Senior Member

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    If you've already driven 200 miles you have plenty of room to add more fuel and dilute the sea foam... And yes the catalytic problems are indicating that you got bad gas that's not combusting normally. Hopefully you put the seafoam in first so it mixed well? Also, maybe you bought a bad tank of gas at same time you put Seafoam in?
     
    #7 PriusCamper, Mar 25, 2026 at 3:33 PM
  8. Brian1954

    Brian1954 Senior Member

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    Waiting for the picture.
     
    #8 Brian1954, Mar 25, 2026 at 5:20 PM
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