I have a 96 Ram 1500 with 5.9L engine. This weekend when I was underneath by the catalytic converter looking up toward the back of the engine, I noticed what appears to be a threaded hole about 1 inch in diameter. Immediately to the left is a cable or hose going into the tranny. The hole is about 4 inches to the right of the distributer and within an inch or two of where the tranny meets the block. It appears very clean so whatever was in there must have just fallen out. I can't seem to reach it from the engine compartment. Any ideas what it is? This weekend my truck started idling erratically, sort of like surging, when it warmed up. Not sure if it's related.

HELP !

 

Sorry for what may sound like stupid questions here.

Are you talking about the rear of the engine block? Is it engine right or left? Can you stick your finger in it, and can you feel anything when you do? ( OK Perv, stop laughing)

If it's on the block and goes into the block, I'd say it is part of the crankcase ventilation system, but you should have something that hooked to that. If that hose, pipe, whatever came lose you could have a rough idle

 

I can't see well enough to tell if it's on the back of the block or the manifold, but probably the block. From my poor viewpoint under the exhaust, it's too far away to reach but I'd guess that I could put my finger in it. It would be on the right side of the engine (towards the passenger side) at about the 2:00 o'clock position where the transmission bolts to the block. That is about 4 inches right of the distributor. I don't see any hoses or connectors dangling anywhere, but it is so clean that there must have been something threaded in there. I couldn't find anything in the Chilton manuals.

 

Is the hole on the same plane as the distributor? I can't think of anything in that area of the block except for a hole that take the oil pressure sending unit, but that is on the flat surface on top of the block with the distributor.

 

lol, [&:]

 

If it is on the intake, it could be the egr port, there would be a tube connecting the exhaust manifold to the intake. From what you describe, sounds like it was plugged, & now it's unplugged... how is the truck running?

 

OK, after doing a bit more research, I found that the sensor I thought that went into the tranny is actually the oil pressure sensor. So the question is: What is immediately to the right (passenger side of vehicle) of that sensor?

 

From what you described it sounds like it could be an downstream oxygen sensor. an 02 sensor may also cause irratic idling but normally your check engine light would come on too.