RE: Twas the O2 sensor WAS: Rough Idle with headers

From: STRICKLAND, Tate (tstricklan@shl.com)
Date: Wed Oct 07 1998 - 10:50:16 EDT


Perhaps you could contact the dealership to verify what sensor you had
(sensor #2). I think you're on the right track suspecting the
sensor's operating temp.

Tate

-----Original Message-----
From: Michael Clark [SMTP:mike@snakebite.com]
Sent: Tuesday, October 06, 1998 9:20 PM
To: dakota-truck@buffnet.net
Subject: DML: Twas the O2 sensor WAS: Rough Idle with headers

From:Tim Roller>>magnum318@bewellnet.com

>>the only things I can think of is possibly a spark plug crapped out
and is
> getting intermintent firing--what plugs are you using
<BIG SNIP...>

Thanks Tim for all your suggestions I appreciate it. As it turns out
it was my O2 sensor (thanks Travis Ingrao for the tip). About 25,000
miles ago I replaced it
(preventative maintenance, it was still ok), and the
best I can tell the dealer gave me the wrong one. The original had a
shorter wire and a different number engraved on it. I switched the
original back in and have had no more problems for a week now. But
I'm still kinda confused. If it was the wrong sensor (or even a bad
sensor) why would it work ok with the stock manifolds, and have
problems with headers? What would change as far as the O2 sensor is
concerned? Less back presure, higher exhaust gas temps...? The
problem only showed up on warm retarts, sometimes on cold starts, and
only during the first minute or two while the engine was coming up to
temperature, after it warmed up it ran great like it should. It would
start fine, idle fine for a few seconds, then
get REAL rough (like it had a monster cam or something) then after a
few seconds clear up like someone turned a switch. These sensors are
heated right, could it not have ben heating up on it's own? That
would make
sense, the SBEC would start reading the sensor, but it would not be
hot enough yet so it would give a bad reading. But wouldn't that
throw a code? And why would it clear up so suddenly?

WIERD....

I'm just glad it's fixed, but I'd still like to know what was going
on....
---Mike, near Houston.---
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