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98 iac and idle problem

Discussion in '1994-2004 V6 Mustang Tech' started by edgar castrp, Jan 3, 2018.

  1. edgar castrp

    edgar castrp New Member

    Nov 5, 2017
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    So i have a 98 3.8l with an 01 3.8l swap in it and everything was running fine up until the other day. The car started idling real rough to where the motor would shake side to side and the car would pretty much die. The times this has happened i disconnect neg terminal for 30 minutes and start her up just fine its after about 10 minutes or when i turn the heat all the way up that the car starts acting weird. Fyi I haven't really ran the car since the swap have just had it there and turn it on and off every once in a while. My question is the following, is the car fine running the 01 motor with 01 iac and a 98 computer? or should I change the iac to the 98 one? I tried to put the 98 one but it doesnt fit. I just feel i need the 98 one since everything else on the motor is a 98 when it comes to most of the sensors.
  2. douglass

    douglass Active Member

    Aug 8, 2013
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    Bay Area, California
    So far mine has run good. I am finished with the tuning, and I will say this. When I tried to use the same tune on on the split port engine as I did on my single port the car ran very rich. I had to change a bunch of stuff in the tune. I wouldn't think changing the IAC would change much, but if you can get the 98 to fit its worth a shot. I am planning on putting the M90 supercharger back on. The car does not feel like it has any more low end torque, than it did before the swap. I do feel it has more throttle response, and a little stronger in the higher rpms.