Strange behavior- ECU/ignition?

Jim Green jeg1976 at
Mon Sep 13 13:50:18 EDT 2004

--- DGraber460 at wrote:

> I have over the years had my car (83 URQ) on rare
> occassion behave very  
> strange with no clue as to why.
> What happens is out of the blue, driving down the
> hiway at 60-70, the tach  
> will suddenly to drop to zero and bounce up & down
> as it comes on and  off 
> line. The car then backfires violently at the same
> time. It starts with once  
> every 15-20 seconds and becomes more and more
> frequent until the car finally  
> stops altogether. Switching the car off, and
> restarting (rebooting the computer)  
> and all seems fine.
> It has only happened 4-5 times over the years, but
> did it twice yesterday  as 
> I was returning from the West Coast UPG in the
> middle of Utah, and western  
> Colorado (miles from anywhere). It is not heat
> related, and pedal input &  
> jiggling the ignition switch have no effect. Is
> there anything in the ECU maps,  
> programs, or electronics that could cause such a
> thing?
> This has me totally stumped!
> It will go months or years between episodes-
> although yesterday it was 3  
> hours and 240 miles apart.

Very strage, do you have flywheel sensors for the ECU?
 I'd suspect these, or even the wiring to them.  I've
had used ones I've pulled from junkyards do some
really strage things on me, and the only way to get up
and running again sometimes was to dissconnect my
battery!  I know we have different ECU's, but a VR
sensor is a VR sensor, ya know?

Jim Green
'89 90tq
'89 80q

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