service engine light in highway

[Rondiggy]

I own a 1986 with a 4+3 transmission. Although I keep it in great running condition when I am on the highway for more than about a half hour my check engine light will come on. If I pull over, turn the engine off and then back on immediately the light will be off and stay off until I am at highway speeds for a certain amount of time. All of the gauges are normal, oil pressure/level, engine heat, etc. There doesn't seem to me anything being harmed. My thought is that it may be the catalytic convert needing replacing. Any thought? Thanks! Ben

 

[Vettefan87]

I own a 1986 with a 4+3 transmission. Although I keep it in great running condition when I am on the highway for more than about a half hour my check engine light will come on. If I pull over, turn the engine off and then back on immediately the light will be off and stay off until I am at highway speeds for a certain amount of time. All of the gauges are normal, oil pressure/level, engine heat, etc. There doesn't seem to me anything being harmed. My thought is that it may be the catalytic convert needing replacing. Any thought? Thanks! Ben

Have you ever pulled codes before? Short out the A and B connectors on your diagnostic port (underneath the driver side dash by your right leg). Turn the key to the on position and see how many times the SES light blinks off and on. Once you know that you will be able to figure out what code it is.

 

[jiangtao]

Sounds like the EGR code. I would check the EGR temp sensor/switch and make sure the wire going into it is tight. [wire to sensor going into the EGR tube can loosen and cause the code.Wire going into sensor at the top has a threaded entrance into the sensor.] If not loose, then try replacing the sensor [cheap] if that doesn't work, then you might have to replace the EGR valve and or tube.