It all began with my check engine light coming on about 2 miles away from home. As soon as it came on I noticed a big loss of power, as if I was towing a heavy trailer. I was running several errands, and each time I stopped and shut off the mighty 3.0. When I returned within minutes and started her back up there was no light and the power was back. Within a few miles the light came back on and the power was gone. This happened 5 or 6 times, so I dropped her off at my mechanic's shop for him to check the next day. Wouldn't you know, they drove it around and never could get the light to come on. Computer scan revealed no codes. He asked me to check my records and we decided it was time for plugs, wires and a distributor -- plugs had 35K on them, wires and distributor nearly 100K. He also replaced the fuel filter. I paid the man and went happily on my way until . . . you guessed it, 3 miles down the road the light came on. I did a quick u-turn and went back to him and did NOT shut down the motor. His computer scan NOW showed a code for a knock sensor. But before they ordered it they did a "smoke test" which he said shows a significant vacuum leak on the PCV hose. He is going to get the hose and see if that solves the problem. He said that such a leak could cause the knock sensor to kick in, causing the check engine light and loss of power. What do you think? The Runner has been an expensive vehicle for me this year. I'm hoping the hose does the trick.

 

No takers?

 

The PCV wouldn't cause that. Your knock sensor failed and it is retarding the timing.

James

 

when 3.0l knock sensors (or wires) go bad, does it always set a check engine lite/code?

 

From all I've read on other threads, yes it does.

Back to SRV1, my mechanic thinks that such a big vacuum leak could cause the knock sensor to think that it has to retard the timing. Like I said earlier, I hope he's right, but I have my doubts . . .
Fortunately I can drive my company truck in the meantime and don't have to do this :walk:

 

If this problem you have were to be caused by a vacuum leak then shutting off the truck and restarting it wouldn't get rid of the drivability problem since it is a psychical problem rather than an electrical problem. A vacuum leak will make the truck run badly all of the time, not when you shut the vehicle off and restart it.

James

 

Check and clean the harrness connection where it connects under the tb, drive it and if that doesn't help its time to replace. If you do the job yourself it close to $400 for all the parts needed, sensor, wire, and gaskets. Good luck hope its just the wire.

 

I know we're talking about the 3.0, but I had BOTH knock sensors go out within a month of one-another on my 3.4L. The ace Toyota tech that I use as a consulting/sounding board had never heard of it happening, but sure enough...

fwiw, I re-used the original gaskets, I just lined the block edges with red RTV and things sealed up just dandy. It saved me about $80 _each time_. The gaskets are bloody expensive!

 

Shop just called. They say it's ready to go -- no light and running like a champ. They only replaced the hose. Hmmmm
We'll see!

 

So far so good! I picked up the truck and have been driving around as much as possible for 3 days. No light and running like a champ! I'm keeping my fingers and toes crossed.

 

UPDATE:

I have done 250 miles, no light and running smooth as silk. AND no doubt because of the plugs, distributer & wires my mileage jumped from 15 to 18 mpg.