On Sun, 31 Oct 1999, Christopher L Scott wrote:
> I just replaced the oxygen sensor on my 94 Dak 3.9, when the light came on
> and the o2 sensor code flashed. The truck ran great after i replaced the
> sensor, but last night it started to hesitate on acceleration, and when it
> did, the engine light came on again. When I reached my destination, I
> flashed the code, and sure enough, 21 came up. Oxygen sensor. But the
> problem is intermittent. When I started up the truck later, it was fine,
> no light or anything. do I have a defective sensor, or (more likely IMHO)
> is there a problem somewhere else in the O2 sensor circuit? does anyone
> have experience with this? Any advice is appreciated.
Is your exhaust system tight? A Dodge tech told me once that
if you've got leaks in your exhaust system, air (and therefore
oxygen) can get in and mess up the readings for the O2 sensor. (It
would detect too much oxygen and try to compensate by adding more
fuel. Can you smell fuel when it hesitates?) That's something to
check on anyway. If you can get it to happen consistantly, you might
want to try unplugging the O2 sensor to see if it still does it.
(That would force the engine to run in open loop, and if you still
have the hesitation, I would start to suspect something other than
the O2 sensor and circuit.) (You can unplug the sensor either down
by the sensor itself, or under the hood, where it joins the wiring
harness just before the computer.
Also, you may want to check the connection to the oxygen sensor.
Once, when I was working on mine, I noticed that one of the pins had
been pushed up into the plug, so there wasn't really much (if any)
connection. I just recently had a problem that plagued me for months
which caused my engine to stumble and quit randomly, and it was
tracked down to a loose connection in the coil plug, so something
as silly as a loose plug can really do some strange things!
Good luck!
-Jon-
.--- stei0302@cs.fredonia.edu ----------------------------------------.
| Jon Steiger * AOPA, DoD, EAA, MP Race Team, NMA, SPA, USUA * RP-SEL |
| '96 Dodge Dakota V8, '96 Suzuki Intruder 1400, '96 Kolb FireFly 447 |
`--------------------------- http://www.cs.fredonia.edu/~stei0302/ ---'
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