[V8] 00523 Code/Rough running (was No, Officer)

[Andy Schor]

I'm still trying to track down the recurring yet intermittent problem in 
which CEL and 'limp home' are triggered on a warm start (immediately at 
start-up).  My observations are;

* Starts up fine cold (first start) or after sitting for a while.

* Warm re-starts, sometimes fine sometimes CEL with Limp Mode

* As I turn the key to the START position and the CEL goes out, it will run 
fine.
   I had also noted an idle 'surge', however I think it is more of a drop 
than a surge.

* If I turn the key to START and the light stays on, it runs rough with 
abrupt on/off throttle.
* When in the CEL/Limp Mode, the idle is stable.

* I have tried turning the car OFF/ON, it usually re-starts in CEL mode but 
sometimes it's OK.
* Today it stalled after a wavering idle and restarted in CEL mode.  I drove 
it a few miles, occasionally trying a re-start but got the CEL consistently. 
Then it wavered and stalled in traffic.  Upon re-start there was no light 
and it's running well!

* The code 00523 "Intake Air Temp Sensor short to positive" comes up.  This 
has been replaced (connector as well), along with O2 & knock sensors and 
ISV.

I've tried to be as observant as possible, noting anything common or 
peculiar.  Perhaps there's something I'm missing.  Most of the time this car 
runs great.  It is a pussycat around town, a beast when you want it to be 
and still a great road car.  I'm sure this is something that is curable. 
I'm amazed at the amount of experience and knowledge within this group.  I'm 
not a mechanic or engineer and I didn't stay at a Holiday Inn Express so I 
need your help.  This seems (to me) to be temperature related but *may* 
start fine when warm.  Could this be related to the ignition/distributors 
system?

The conditions have never intermingled.  What I mean is that if the CEL is 
on, the idle will not drop and the throttle is abrupt (consistently).  When 
the CEL is off, it runs fine and the idle is sometimes stable sometimes not. 
The throttle transition is smooth.  I should probably mention that this is a 
5 speed car.

If the CEL comes on at start-up, it will not transition out of this mode 
while driving - only (and not always) with a turn of the key.  If the CEL 
does not stay on at start-up, it will not transition into the CEL mode while 
driving but if allowed to stall while surging at idle (No Officer...) it 
will generally re-start with the CEL on.

Thanks as always,

Andy
'91 V8QM
'91 Avant 



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