engine miss

Discussion in 'Engine, Fuel and Exhaust' started by myfrdm, Sep 14, 2015.

  1. myfrdm

    myfrdm Member

    97 Ultra, 96" Stage 1 from new. Rinehart True Duals,
    Installed Andrews 48H cams last summer. Had dyno after cams. Couldn't communicate with SE tuner. Replaced with Power Commander 5. Ran strong but crap fuel mileage. Black carbon smoke on hard accel. Flutter at around 2200 RPM. Had dyno again this August (different shop) to try & improve mileage. They said it was VERY fat. Ran more evenly thru a pull. No complaints on power. Still, plugs are black after a 3,000 mile trip to Colorado.
    Mileage on highway, steady 75MPH thru Kansas, 32 & 33 MPG. 25 miles from home developed miss. Changed plugs. Still has miss, still bad flutter at the 2200 rpm range.??????:
    Any Ideas?
  2. Jeff Klarich

    Jeff Klarich Well-Known Member Contributor

    Sounds like it's still running to rich, poor mileage and black/sooty plugs. Have you changed your plug wires? dirty fuel filter? the miss could be several different things. You may want to lean it out a little more to start with. JMHO.
  3. Jeff Klarich

    Jeff Klarich Well-Known Member Contributor

    A couple more things come to mind, give the injector wires the wiggle test, wires have been known to fray or break and loose signal to the injectors. Could you maybe have a air leak at the intake? Have you tested the coil? Just a few things to consider.
  4. Jack Klarich

    Jack Klarich Guest

    Check your plug wires with an ohm meter, bend and stretch em and recheck, check coil with a mist spray of water see if it stumbles, mileage is not overly bad IMO but sounds like you are TOO rich Is timing adjustable with your unit?