RE: Two new problems - P0051 and sporadic loss of power

From: Rick Barnes (rascal@scrtc.com)
Date: Fri Jan 11 2008 - 23:34:26 EST


David, that sounds like a clogged cat to me. As the cat warms up, it will
get worse and worse as exhaust cannot get through it.

Rascal

-----Original Message-----
From: owner-dakota-truck@bent.twistedbits.net
[mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of David Gersic
Sent: Friday, January 11, 2008 9:38 PM
To: dakota-truck@dakota-truck.net
Subject: DML: Two new problems - P0051 and sporadic loss of power

'01 Dakota with 3.9L 4x4/5Sp here. Was running great, no problems, but over
100K miles so in the fall I went after the wear items to get ready for
winter. Did new plugs, wires, rotor, distributor cap, and O2 sensors (all
four).

Since then, I've got two problems.

1) Twice now, the computer has thrown a P0051 code and turned on the check
engine light. Didn't do anything, the light went out. The code is still
stored, though. From what I read in the service manual, the computer
considers the last three trips to have been ok, so it turns off the light,
but keeps the code stored.

I know P0051 is complaining about the heater circuit on the passenger side
upper O2 sensor. It's a new Bosche sensor, but I suppose it could be faulty
or defective. Both times, the weather has been especially wet (100%
humidity,
fog, rain, etc.) and cold (25 deg. F or so). Could that be affecting the O2
sensor?

The other possibility is that I mahtzo'd the wiring to the connector. If so,

is there any way to reach this connector without pulling the engine? I
cannot
find a way to get to it, either from above or below. From below, I can just
barely snake one hand up there to reach the connector plug.

2) Random loss of power. This has happened a few times, usually when the
engine is warm from having been driven, but then parked for a little while.
Like drive to the store or a restaraunt or something, go in, come out, and
start it up again. What happens is I'll give it some gas and start to let
out
the clutch, and it has *no* power. It doesn't stall, but it won't accelerate

either. Today when it did it, I think I heard it backfire. Push the clutch
back in, and it idles fine. Gas it, with the clutch in, and it revs fine.
Let
out the clutch again, and it takes off fine.

Could these be related problems? If one of the four O2 sensors is reading
screwy, some of the time, but not off enough for the computer to discount it

entirely (or throw a code on it), I could see that causing a fuel mixture
problem, too rich, which could be that backfire I think I heard.

Or, is there something else more likely that I ought to be looking at first,

before pulling the O2 sensors out again?



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