ok i am new to this forum. i have a 1987 mustang gt. it has like 170000 on the motor and car. well i bought it and it would idle messed up. so i chenged the tps and that didnt help. on the down rev it would stay at about 3000 for like 5 seconds. and then go down to about 1500 and idle there. well i unplugged the idle air control valve and it stopped doing that. so i bought a new one and i plugged it in and it still did the same thing as before. any thoughts? and another problem. i fire up the car and right after it gets warm it runs fine. then about 10 minutes later it will cut out and junk. but then it will run fine at full throttle above like 3000 rpms. and then it runs fine again. i dont understand. any thoughts on that? ok and the final problem. i put a new fuel pump in my car and now when i turn right the car almost dies like it has fuel loss. i can hear the fuel pump when that happens its really loud. but when i turn left its fine. any thoughts? oh yea i have stainless equal lenght headers and a cam. so i dont know if that matters. oh yea i have 2 broken vaccum lines that i dont know where they go. the start on the passenger side up by the firewall. any thoughts? well if anyone can help i would appriciate it thanks ryan

 

I have a 95 Cobra so don't know exactly how the vacuum line hooks up. But I would say that is definitely part, if not all, of the problem. Get yourself a Haynes book from any autoparts store and fix it. Also, did you change the fuel filter. My brother had the same issue you have - i.e. when you turn one way the car acts up. He went thru 2-3 fuel filters and come to find out the gas tank was dirty as &*#. He ended up dropping the tank and cleaning, changed the fuel and everything is good so far. Peace

 

Did you figure out the problem

 

it was back in 2005 so not sure if you will get a reply.