3.0 Misfire

Discussion in '3.0 Engine' started by Stan Reeves, Nov 18, 2017.

  1. mhoward

    mhoward Member

    Some of them never saw "top end", since most of the roads didn't have enough straight pavement to get them there.
    DeanMk likes this.
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  3. OP
    Stan Reeves

    Stan Reeves New Member

    I did a leak down test on # 3 cylinder today and it passed in flying colors. I pulled the plenum again and looked for cracks in the plastic but it looks great. I didn't think it was a valve because it runs great at startup. It is when it idles after warm up I get a misfire.
  4. OP
    Stan Reeves

    Stan Reeves New Member

    Well, I finally fixed it. After putting a LOT of money and time I knew it was not a valve after doing a leak down and compression test and it would run perfect until it warmed up and I could drive it a hundred miles with no codes, it was when I stopped at a red light or a stop sign it the check engine light would come on.

    I noticed that after warm up it was only idling at 450 to 500 RPM’s and p0303 would come up.

    I looked at the throttle body and there was no screw to adjust the idling, mine has a rivet that cannot be adjusted,

    The end of the rivet that contacts the stop on the throttle body was worn down and letting it idle too low. I tested it by gluing a dime on the stop on the throttle body that rests against the rivet at idle and it increased the idle up to around 900 RPM’s. I drove it about 200 miles and it ran perfect. I pulled the throttle body and drilled the rivet out and put a screw that I can adjust. I have driven it over 500 miles since I added the adjustment screw and it runs perfect. AAAAA IDLE PLATE.jpg
  5. chasmc

    chasmc New Member

    I got an 05 3.0 that's doing the same thing, except on different cylinder.
  6. OP
    Stan Reeves

    Stan Reeves New Member

    I finally found out what was really wrong with my Ranger. I took it to Mexico and got a top end rebuild. Ford had never put a bolt in the end of the exhaust manifold right by number 3 cylinder.
    The mechanic that rebuilt the heads called me and showed me the # 3 exhaust valve. It was slightly warped. He said it was probably because the factory forgot to install a bolt in the exhaust manifold, he showed me the rusty threads, there has never been a bolt in it. When I bought the truck it had 4 miles on the odometer. It runs great now and the top end rebuild only cost me $150
    ( I supplied all the gaskets, oil, filter and antifreeze )
  7. DeanMk

    DeanMk Member

    Just goes to show you, its still the little things that'll get ya. Every time.
    Glad you got your problem solved Stan and thanks for taking us on your journey.

  8. OP
    Stan Reeves

    Stan Reeves New Member

    It sure is nice to have it running right again, after the top end rebuild I am getting 22.6 miles per gallon.
  9. DeanMk

    DeanMk Member

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