Cured the loping idle...man am I blind!

[tmcalavy]

Decided to check all vacuum lines today on my 93 Ranger XLT with 3.0 V-6. All the lines are good and flexible, can't hear any sucking noise...but the truck lopes at idle...up and down, up and down...kinda goes away after it warms up but not really. So, after checking the vac lines I decided to pull the air intake hose and check the butterfly in the intake...maybe needs cleaning? Man am I blind! While twisting the air intake hose off the intake, I notice it is completely worn through in three spots where the hose accordions just behind the intake manifold clamp. Lots of dirt, grease, etc. there and it's underneath, so you don't see it from above...only way to find it is to feel the underside of the hose.
A few wraps (depends on how you define "few") of duct tape around that part of the hose is a temporary fix...but now the truck idles like it was brand new. It roams very little in RPMS at idle, cold or hot...maybe 50-100 and recovers almost instantaneously....very smooth now. So folks with a lopey idle, check your air intake hose...you might be surprised.

 

[Mudhound]

Yeah, 4.0 is good for "rubbing" the hose like that on the radiator, I've noticed...

 

[SenorNoob]

In my case with the 4.0 it wasn't the radiator but the shroud. It just barely touches this on little know right on the top so I just cut it off. Doesn't touch now. At least not with the hood open.

 

[tmcalavy]

Hmm...glad I don't have the 4.0. On the 3.0 the hose stays off the top of the engine, but the accordion part of the hose just before the air intake catches a lot of grease, gunk, general crap and unless you grab that part of the hose and check, it looks solid. But you can't see it from where you stand. Of course that hose is now 21 years on my truck...guess they gotta wear out sometime.