L98 Code 13

[JonJon]

Hey Gang
'86 Coupe L98/DN 4+3

The car sets an intermittent code 13 and trips the SES light. It only happens at cruise/light throttle at highway speeds and takes 8-10minutes to set.

Fuel pressure/volume are verified and base timing/min airflow are properly adjusted. Wiring/Vacuum lines have been checked/inspected and the left bank O2 sensor has been replaced. The FSM doesn't show a right bank O2 sensor and I can't find one.


What am I most likely missing?
Jonathan.....

BTW The DN unit won't shift into overdrive so I'm driving the car as a regular 4speed till I have time to pull the trans.

 

[Antz81]

I would check the grounds and connections out to the sensor.

 

[Hib Halverson]

Hey Gang
'86 Coupe L98/DN 4+3

The car sets an intermittent code 13 and trips the SES light. (snip)
What am I most likely missing?

Your engine has only one oxygen sensor.

Code 13 sets if there is a problem with the sensor, the sensor wiring or with the ECM.

Do you have the Factory Service Manual?