I bought my 1999 mustang gt about 4 years ago. Ever since I bought it it has idled rough. It has no cats I have replaced the iac, replaced egr, changed all spark plugs/coils, cleaned maf, when I had bought it I noticed coolant everywhere in the engine bay when I had got it home. Which was do to the person that owned it before me had put a after market intake manifold on and left the old gaskets on while putting the new one on with the old ones.
When driving it still gets up and goes it's not sluggish at all. While driving everything is okay but when in stop at a stop light/ stop sign that is when the idle surges and drops, sometimes it even stalls. I noticed it runs better when I have the vaccum line removed that goes from the crank case to the car. It runs alot better that way compared to having it an active line. When it was active it would shut off every time I stopped. But with it removed it doesnt do it everytime just every once in a while. I also tried cleaning throttle body but no help there either.
When driving it still gets up and goes it's not sluggish at all. While driving everything is okay but when in stop at a stop light/ stop sign that is when the idle surges and drops, sometimes it even stalls. I noticed it runs better when I have the vaccum line removed that goes from the crank case to the car. It runs alot better that way compared to having it an active line. When it was active it would shut off every time I stopped. But with it removed it doesnt do it everytime just every once in a while. I also tried cleaning throttle body but no help there either.
