Engine Surging On Constant Speed

Discussion in 'SN95 4.6L Mustang Tech' started by GTpowerwithin, Oct 2, 2012.

  1. Hey guys me again, I know I have posted about this before but mostly just a update so hopefully you all can help, here is what's happening if you don't already know..

    When I'm driving my car around 50-65 mph, the car will surge as in, Rpms will jump twice. Check engine flashes very fast when it happens then goes away. Also when I'm stopped wether I'm I'm Drive, Neutral, or Park it will rev up and if in drive wanna jump on me.. And no DTC's

    The things I have changed.
    1. TPS
    2. IAC Cleaned and changed
    3. Spark plugs
    4. Cleaned and changed MAF
    5. Sprayed for vacuum leaks(Everywhere)

    Please I need help, I think I'm getting bad gas mileage as well.
  2. Are you sure there are no codes? The flashing MIL means the PCM has detected misfires and it should be logging P030x codes.

    What mods are on the car?
    What year is it?

    When you say you "cleaned and changed" the IAC, does this mean you tried cleaning the IAC first and then later replaced it with a new one?
  3. What code is that? There was but I wanted to clear the codes and reset my battery, and hadn't nothing came back..

    Mods: 3.73 gears, shift kit, cold air, SCT tuner, straight pipe dumped...

    And I cleaned it first then I replaced it as well..