1999 ranger 4.0 rough idle and dies sometimes at idle HELP!!!!!!!!!please!!

[chubbygoatboy]

99 ranger, 2 wheel drive, 4.0 auto trans. Just started doing this. It sometimes is hard to start, then when it does start, it idles very rough. It will keep running as long as you are slightly revving it. Put it in gear, and go, it does fine. But, if you do not baby the gas by slightly giving it pedal, it will idle rough, then die. It runs great going down the road and has plenty of acceleration.

It is not doing it all the time, and is not predictable. The plugs and wires were changed a few months ago. I cleaned the throttlebody, as it was gunked up pretty bad, because I have seen this be the idle problem with some Fords before.

Any ideas are greatly appreciated!! THANKS

Still happens, but now has a OBD code of P1507, Manf. control Veh. Spd. Idle Speed Control, Aux inputs. What the heck is that? I pulled off the IAC, it was slightly carboned up. I cleaned with carb cleaner, and put back on. THe truck behaves just fine, for now, but thats what it did before. Just occasionally hard to start with the rough idle. NOw, the IAC makes alot of noise. Is this my problem? Also, I noticed while cleaning it, the valve seems rough to move, maybe sticky. And, it does not appear to ever close completely. SHould it? THANKS for any ideas!!

[chubbygoatboy]

Originally Posted by chubbygoatboy

99 ranger, 2 wheel drive, 4.0 auto trans. Just started doing this. It sometimes is hard to start, then when it does start, it idles very rough. It will keep running as long as you are slightly revving it. Put it in gear, and go, it does fine. But, if you do not baby the gas by slightly giving it pedal, it will idle rough, then die. It runs great going down the road and has plenty of acceleration.

It is not doing it all the time, and is not predictable. The plugs and wires were changed a few months ago. I cleaned the throttlebody, as it was gunked up pretty bad, because I have seen this be the idle problem with some Fords before.

Any ideas are greatly appreciated!! THANKS

Still happens, but now has a OBD code of P1507, Manf. control Veh. Spd. Idle Speed Control, Aux inputs. What the heck is that? I pulled off the IAC, it was slightly carboned up. I cleaned with carb cleaner, and put back on. THe truck behaves just fine, for now, but thats what it did before. Just occasionally hard to start with the rough idle. NOw, the IAC makes alot of noise. Is this my problem? Also, I noticed while cleaning it, the valve seems rough to move, maybe sticky. And, it does not appear to ever close completely. SHould it? THANKS for any ideas!!

Well, it is still doing it. I replaced the IAC and for now it has fixed the problem.