2001 Dodge Ram Dodge Ram Running rough at Low RPMs

DEVILDOG_0431

MEMBER
2001 DODGE RAM
V8
4WD
MANUAL
87,000 MILES

Just bought the truck, put in new plugs, wires, cap, oil, air filter, tps, ran z-max through it, new 02 sensors. It keeps throwing P0132 and sometimes po138. The 15amp o2 sensor fuse was blown and I replaced it and p0132 came up again. At idle the truck runs rough and drops down to 100-200 rpm range and then shoots up to 2000 rpms on it's own, it has come close to dying but hasn't actually shut off on it's own. When shifting through the gears I let off the gas to push in the clutch and the throttle just stays up around 2-3000 rpms for a few seconds then drops, the throttle return spring has plenty of tension. If I am moving from a stop light it will take off roughly and takes forever to clear out and run smoothly. I rev it to clear it out and it's fine after 2000 rpms, anytime under that it bogs badly and slowly clears out if you hold the gas lightly then firmly. When decelerating I heard popping frmo the exhaust (hinting rich fuel). Sometimes there is a popping under hood. Sometimes at idle I can hear hissing coming out of the air intake box and feel it sucking air. What is the problem? EGR? Idle Air Control Valve? I'm stumped, fuel pump? The truck sat for a couple years before I bought it. I cleaned the throttle body butterflies and body opening.

2 Replies

CARADIODOC

MECHANIC
33,916 POSTS

Recommend taking it to a trained professional because you are about to throw a lot of unrelated parts at it. That will cost more than a professional diagnosis.

You can start by looking at the wiring harness going to the oxygen sensors. In particular, look for wires melted on a hot exhaust pipe, or cut from rubbing on sharp edges of a metal bracket. Check the MAP sensor. They will cause erratic idle. Worn bushings in the distributor can do this too.

Popping out of the intake is often due to burned valves or carbon chips preventing the valves from sealing. Plugged catalytic converters will cause low power and popping.

Not sure what you mean by "sucking air"; that's what the engine is supposed to do. If you hear a change in the sound, you're probably hearing the Idle Speed Motor opening up an air passage to try to control idle speed.

Caradiodoc