Rough Idling and dies

[mrdpman]

4.0 6cyl dies or idles rough, very sluggish when accelerating, but runs mostly fine when up to speed. Let off pedal and dies. Not sure where to start.

 

[mrdpman]

Found info in library

Will try cleaning the MAF and see what happens. I am new to the site and did not see the library until after posting this question. Thanks in advance for your help.

 

[Bird]

Might try cleaning your IAC also.

Bird

 

[mrdpman]

Still need help. Have cleaned the MAF and IAC, still cuts out and idles rough. Unpluged the MAF and it seemed to idle ok. So, I checked the MAF wires again and all looks fine, any advice?

 

[vertlmt94]

My 5.0 did that when it had a vacuum leak. My pcv valve came unhooked and truck wouldn't idle for nothin.

 

[Nhaz]

The easiest place to start is checking for vacuum leaks. Get a propane torch DON'T light it. and wave it around the engine compartment. the released gas will be sucked into the engine if there is a vacuum leak and the engine will rev up as it burns the propane.

 

[88rangerxltkc]

4.0 6cyl dies or idles rough, very sluggish when accelerating, but runs mostly fine when up to speed. Let off pedal and dies. Not sure where to start.

Well i had a similar problem on my 94 4.0, all it was was a vaccum plug fell/rotted off. This has happened to me several times.

 

[Madracingalley]

check that line from the vaccumm tree in the back that goes to the front of the fuel rail in front of the coil pack. I just replaced mine and it runs WAY BETTER

 

[knetter]

Have you figured anything out? I think i am having a similar problem with my 97 4.0 with auto tranny. When you let off the gas when driving it'll drop the RPM's and stall out, this problem did NOT happen gradually. Thanks.

 

[Z3CHYD]

I have pretty much the same problem, just a side question, I put in a cone style filter and I just unplugged the two lines that plugged into the airbox, are one of those or both vacuum lines? should I plug them and would that solve the problem?