dont know what to do

[jpier93ranger]

hey guys,

new to site. i have a 93 ranger 4.0. motor was rebuilt last march. my problem is, when my truck is cold it starts and runs fine from point a-b. when i turn off the truck for a few minutes i will crank and run fine. if i let it sit for 10min-1h it will craank but will idle for a second and choke off, sometimes it will idle very rough around 500 rpm i try to give it gas to increase rpm but it just idles down and chokes off. 5 mechs have seen this truck w/ no answers. oh the engine light is not on. need help or this truck is goin to da scrap yard. also after trying to get the truck running again if i wait for a while it will crank again and run fine. help

 

[shane96ranger]

If you keep it running (when it's acting up), does it eventually even out and run ok?

My first thought it the fuel pressure regulator. If it were dumping fuel out the vacuum port after you shut it off, it would cause an extreme rich condition and won't run right until that fuel is spent.

 

[Naterenfo1]

Also, check your PCV valve. If thats acting funny then the truck can run funny. its a $2 part to replace, definitely worth your time to check out

 

[Earl43P]

Sounds like a bad ICM (Ignition Control Module) to me.

I'd also pay attention to whether the fuel pump is running or not when it won't start. Should hear it run for 2 sec. each time you go from key OFF to Run. Might be a bad fuel pump relay.

While you are at that, pay attention to whether the Check Engine light comes on each time you turn the key to Run, before cranking the starter (bad PCM relay if not).