I have a 95 4cyl sr5 4runner. I replaced the head on my car last year by myself and it's all sounding like it's working out. I had a bad cat because I was at 0 degrees instead of 10 on my timing probably. I got it repaired had the timing fixed. Turned out the smog shop smashed the contacts at the diagnosis port. I took it in and passed smog after all that. During that period I noticed that at 4th and 5th when I accelerate hard I hear soft knock every so often. I wouldn't hear it if I had the radio on. I thought it would go away after the timing issue was resolved but it hasn't. I'm wondering if this is something everyone hears and I'm just being hyperaware because of my blown headgasket or is this something I need checked out. So if it isn't the timing my idle is good, I know my injectors are clean since I sent them in to witchhunter, what could cause that situation? Any help or insight is much appreciated.

 

Not sure of an answer, but I want to follow along.


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Are you sure it's coming from the motor and not the drive train?

 

My guess, you are either listening to valve ticking, spark knock, a carbon knock or bottem end knock.

Being that it is happening on hard accel in upper gears and not at idle/low gears, that throws valve noise out.

Can you give some better description on the noise?

 

Put in the highest octane gas and see if it improves.

 

I was running 91 in it but there was no change. However it didn't get worse when I went back to 87. I can only say this in regards to volume of the sound but not frequency.

edit: Just to add the car runs great and no matter how much I get on the gas there is no knock sound in first through third. But just in case is there a chance it could be my cams and my crank are misaligned through the chain. Could being off by one cog give me symptoms of smooth idle but knock under load at highway speeds. My other thought is maybe the fuel filter is clogged but there isn't any bucking or erratic acceleration in the lower gears where I'd assume the fuel consumption is highest.

 

If its a rod it will keep a knock however a main bearing knock will come and go at diff RPMs, If its spark knocking you need to lower your timming a little to about 6 degrees advanced.