Still have P0303 code after plugs, wires and coil

Discussion in '1995 - 2004 Toyota Tacoma' started by Farmer_dan_831, Apr 15, 2018.

  1. hey guys, I think I bought a lemon. I picked up a 99 Tacoma prerunner and it ran perfect when I bought it. But on my 200 mike trip home I got a cel and wouldn’t get up to 80. Went away a minute later. I got it scanned and got p0300 and p0303 misfire cofes. I replaced the plugs and wires and still idles like poopy. Got the p0303 again so I replaced the coil. Still have the code. Cleaned map sensor and still get a p0303 code. My next guess is an injector or new maf sensor. I’m about to bring it to the shop. Any ideas?

    Symptoms are:
    Rough idle
    Rough starts (had to give it gas to start yesterday after sitting 20 mins)
    18 mpg all highway. Most 55mph highway.
    P0303 code
    Cel flashed at me a couple times
    Cruises fine but every once in awhile on the highway it will hiccup once.(happens 2-3 times in my 100 mike commute)

    EDIT: foam coming out my coolant resivoir now

    Thanks a lot folks
    Last edited: Apr 15, 2018
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  3. B-Man

    B-Man Well-Known Member

    Welcome to the forum. Could be an injector......could be a valve.......definitely a trip to the shop.
  4. OP

    Farmer_dan_831 Member

    A valve? U really think so? The engine is so quiet.
  5. B-Man

    B-Man Well-Known Member

    If the engine is quiet then probly not a valve......I'm just throwing out possibilities and valves have been known to throw that well as EGR valves....worn piston rings.....bad injectors......slipped timing belt.....I'm just throwing out possibilities for you.
  6. OP

    Farmer_dan_831 Member

    Yea, my buddy just said could be slipped belt.
  7. OR17TRD

    OR17TRD Well-Known Member

    How many miles are on it?
    Foam in the the coolant that’s not good. What’s the oil look like? Chocolate milk?
  8. B-Man

    B-Man Well-Known Member

    Having to give it gas to start it could be fouled spark plug(s) from ??leaky head gasket?? When you changed the plugs were they wet?
  9. OP

    Farmer_dan_831 Member

    257k oil looks clean, even coolant looks clean. Not over heating. I just pulled over and saw it was foaming out. I had 3 water bottles with me and put them all in. Drove another 15-20 miles to the next gas station and no overflow
  10. OP

    Farmer_dan_831 Member

    No, actually perfect condition. All looked identical in wear. I was contemplating changing them as I was taking them out they were so clean. Even my #3
  11. B-Man

    B-Man Well-Known Member

    Can probly rule out leaky head gasket then......just might be a faulty injector then.
  12. OP

    Farmer_dan_831 Member

    I hope so. But the foamy radiator has me worried. Got another 20 miles to go.
    I don’t mind the money and labor working on this thing. Everything is 1/4 price and 10 times easier to work on than my diesels and vw’s
  13. B-Man

    B-Man Well-Known Member

    Yeah, the foamy coolant might be a leaking head gasket......might be gettin' small amount of air back into the cooling system but not bad enuf to foul your spark plugs or burn off through the exhaust and cause smoking.
    OR17TRD likes this.
  14. B-Man

    B-Man Well-Known Member

    The foamy coolant and the thrown code might be 2 different issues.
    OR17TRD likes this.
  15. B-Man

    B-Man Well-Known Member

    Post up when you find the cause/ interested what it was.
  16. Thomasg

    Thomasg New Member

    I'm sorry to say but I would thought that it was a malfunctioning fuel injector but sounds more like a bad head gasket especially after hearing that you're getting gases or foaming coming from the coolant either you got crack in the block
  17. Bogunn

    Bogunn Well-Known Member

    Welcome to the forum

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