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Slight Hesitation after Knock Sensor?

6K views 9 replies 4 participants last post by  07OregonOutback 
#1 ·
So my 1997 Outback Legacy Wagon, 5 speed manual with 118k miles was throwing a knock sensor code, which the dealer changed and cleared the code. They had the agreement with the previous owner, and did it no charge to me.

Prior to that, I drove the car around about 85 miles with the CEL on, and the car drove fine.

After the dealer changed the knock sensor and cleared the CEL I am getting a slight hesitation in the 900-1600rpm range.

It is rather weird, as it doesn't happen all the time. It happens in gear 1, 2, and 3 only.

Basically say I am driving at 45 mph, then coming up to a light, downshift to second, slow down, and release the clutch (THIS IS WHEN IT HAPPENS), if the RPM at this time is in the 900-1600 range, there is a hesitation, shaking of the car (best I can describe it) as it is going forward.

THen it becomes fine.

It also does it, from a stop light, 0mph, in 1st gear, release the clutch, and then it does a bog.

It doesn't do it all the time, but intermittently.

I also thought maybe I wasn't putting enough gas from a stop, but I am. If I rev to 1500rpm, it isn't doing it in 1st gear.

It isn't a big problem, but can be annoying sometimes.

I am doing a full
Fuel FIlter
Air Filter
Oil Filter
Tranny/diff change
Plugs
Wires

In 2 weeks. I am wondering if there is anything I need to look at , or if this is a common problem.

Thanks!
 
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#2 ·
How long have you been driving with the new knock sensor? If they cleared out all the old parameters, it could just be that the new sensor hasn't retarded/advanced the timing to it's correct setting yet, and it should do that by itself pretty quickly.
 
#4 ·
It should have set the parameters by now.. have you checked to see if it is installed correctly? If it is loose or anything it could be setting a false knock and retarding the timing when it doesn't need to.
 
#5 ·
07OregonOutback said:
It should have set the parameters by now.. have you checked to see if it is installed correctly? If it is loose or anything it could be setting a false knock and retarding the timing when it doesn't need to.
I have no idea what it is and where it is.

A friend is helping me do the plugs/wires, I will ask him to check for me in 2 weeks.
 
#6 ·
#7 ·
The knock sensor is right below the throttle cable cam. It is a black plastic kind of round button with a wire coming off the side and held down with one bolt through the center.
 
#10 ·
Yeah, and make sure the connection between it and the block are clean, as they said in the other thread that is where it grounds. If it has a dirty ground that would cause false readings as well.
 
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