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.

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