While driving home today all of sudden my check engine light came on and my bird started to run like crap. It was down on power, it sounded terrible and it would bearly rev up. I'm assuming that it was in "limp home" mod.
I checked the the codes, number 43 was stored. The knock sensor had a resistance of 3900 Ohms and the wire that connects to the sensors had 5 volts when I turned the ignition on. According to the service manual these are normal. So what else could it be? I started it up again later and it seemed to run fine. What conditions can trigger "limp home" mod?
Not sure if it is related, but my fuel mileage has been down about 5 MPG.
Thanks,
Chris

 

I have another question. Could a code 43 be set if there was too much knock detected? What would trigger the ECM to switch to limp home mode?

 

Have you checked your wiring, another individual recently posted a code 43 and found a broken wire under the right kick panel going to the ECM.

 

I figured that my wiring was ok since I could measure voltage at the sensor. But I guess a bad connection would cause an intermitant problem. If the ECM see no voltage at the sensor (bad wire) then does it instantly trip code 43 and go into limp home mode?

 

Do you have the 5.0L TBI or the 5.0L TPI engine in your car?