i got a 93 f150 4.9l 5spd and recently my truck dies somethimes when i start it. it only did it at my friends house on his driveway which a steep slant. now it does it at my house and when i park in the ditch at his house. when i start my truck up it will go into high idle then drop into low quick and then die sometimes and sometimes it catches itself before it dies and then shoots up in idle then runs fine, and sometimes i give it gas to keep it running. does any1 know what this could be?


my friend had the same problem on his 94 f150 5.0 and when he would start it it would die. so he was told to replace the idle motor which was like $100, that didnt work and then now he found out his fuel pumps were bad so he replaced them. but he thinks the pumps are not the problem. he had his engine recently rebuilt 1 year ago. i think he said that the truck still does it once in a while.

 

I had the same problem with my 89 F-150--5.0.I replaced the idle control valve.Before i replaced it,the motor sounded like it was coming through the hood.I bought the part from Autowarehouse.com--suppose to be genuine Ford but it did not have motorcraft stamped on it.I paid extra did they get me?

 

Definitely sounds like an IAC problem. Make sure it's connected. Testing it with an ohmmeter isn't difficult either. If it's broken, or even out of spec, replace it.

 

Is the IAC sensor the one by the number 1 cylinder on the engine or is it on the throttle body. do you know how to test it with the ohmmeter?

 

throttle body. if its not that maybe its the map sensor? i dont remember if the 93's are maf or not

 

You have 2 sensors that are located on the throttle body...1 is throttle possition sensor the othe is Idle control sensor...pull em out and clean them with cab cleaner and see if the helps...if not I replaced both for under $100 bucks from auto zone. Cured my simular problem.

 

I have 24k miles on a jasper long block. Recently it started to run very rough at idle only the first time I start it each day and it would light the engine light. It would do this for a few minutes then it would go away and run perfectly. I could turn it off and have it sit all day at work start it up go home no problems until next morning. I live in PA and it gets in the 60s at nights right now. Could this be the same problem?

 

In my '87 5.0 i have this problem but its never died, it just runs rough for about 3 seconds each morning shaking the truck like hell then runs fine the rest of the day. Mines EFI and i think its just running the fuel through the injectors after sitting all night, but if you find out what it is let me know I'd sure appreciate hearing what it is to make sure I'm not running into a problem down the road that I can just fix now.

 

Anyone get this figured out? Got a 90 5.0 and sounds like what is happening to mine. It will start up with high RPM and then just drop and die. If I hold the RPM's up for 30 secs or so and then get going, no problems after that. I can stop and wait and it will idle fine. It's just that initial start up where it has problems. I've read on it possibly being O2 Sensor, IAC, or EGR related. I have a new O2 Sensor , just got get the old one off. It's on there good. Guess I could try cleaning IAC first?

 

i just pulled them out and cleaned them and they work good now. so just clean the sensors.