knock sensor trouble
 

I have a 91 4 runner sr5 v6 with 210k

about 2 years ago the check engine light came on and the code came up as "engine knock sensor"

this light would only come on when tranny is engaged.....In neutral and reving the engine...no light but while in gear and while in motion(groung through 20-30)the light would come on, and gas milage goes from 300 per tank to about 170-180

I would reset the ignition (off/on)while traveling at a steady mph and the light would stay off(very annoying)

this happened for about 2 months then problem fixed it self and . it came on intermittently here and there but generally did not have a problem for over a year+


well it came on again..and it is staying most of the time and one in a while I reset the ignition and it would stay off while I ran the rest of my errands. I ndont know if the engine is acctually knoking or the sensor is bad.we even had it on a lift with the engine on and banged like heck on the block to see if the light would come on...but nothing

I was told you have to dig deep in the top end to get to the sensor to check it/replace it(if that is the problem) and it would be expensive($900?).

the truck has 210k miles on it so I dont want to spend too much money even though I LOVE it(bought it with 20 miles...first car) I would like to get another 10 years atleast out of it.

any suggestion......can I trick the sensor from comming on etc. or any othe suggestion.

RE: knock sensor trouble
 

My old jeep use to knock when i put gas from this one station. Then i started putting in sunoco gas it went away about one month later.I think there was water in the gas.Don't know if this can help you.

RE: knock sensor trouble
 

Knock sensor wires are sheilded like a coax for cable tv. If the inner core touches the sheild the light comes on. code would be for open/short. Sometimes when the engine is torqued the harness flexes and grounds the inner wire. I have seen this in other Toyota models. If this is the case you need to confirm the ground and then find a bump in the knock wire.