Hello,

For sake of introduction, I come from a family with three 4runners, all orginally bought spanking new. Our "fleet" includes a 92, a 93 and a 2000. We love Toyota and we love our 4runners.

Car History:
The 1993 Toyota 4Runner has approximately 117,000 miles on it. The oil has been changed regularly (every 3,000 miles or so) and the car has mostly been in 2wd all along and filled with regular grade gas.

A few weeks back I took the 93 4runner in for an oil change and when I got back on the highway, and started to go above 50 miles per hour, a somewhat rhythmic clicking/knocking noise could be heard underneath/behind the rising floor behind the brake pedal.

I've been dealing with this noise ever since. I'm sure it's not the CV joint causing this noise, but I don't know what else it could be. Sometimes I can go 50 miles per hour or higher and not here the noise, but once the engine warms up the same knocking noise goes on. When I do hear the noise, it is usually a somewhat loud knocking noise, with a bit of rhthym to it that does not change if I go faster or on bumpier roads. I can almost feel the knocking noise occur if I put my bare foot behind my brake while going above 50 mph.

I took the car to a trusted mechanic. His best guess is that I've been using low grade gas for too long and need to burn through cleaner gas (fill up with plus a few times and then use supreme) and this should clear the fuel line and stop the noise.

I've almost gone through my first tank of Plus gas and also used an engine cleaner as well.

Has anyone else heard or had this problem before?

Your advice / opinions here are largely appreciated.

Thanks in advance!
SimpleCitizen

 

lube the chassis, u-joints and whatnots, and go drive around.

 

Well i dunno if theres been any not taking care of it or not but uh yea. If its knocking your in trouble clicking could be something else less trouble. It could be a burnt valve unless the "trusted mechanic" looked at them. In terms of motor thats were i would start Might be a bearing going bad mine did start a very big clicking in my left front wheel when my bearing went out. I also could be if your not to familiar to 4WD and have used it recently. IF you have gone in 4wd and wheel you took it out in to 2wd i hope you backed up in reverse for like 10 feet. Because if not you might have ed with the 4wheel drive switches. They are electronic and have a weird mind. Try going out somewhere and puting it in 4wd a min then putting it in 2wd and BACKING UP ABOUT 10 FEET it might fix your prob.

 

Hi,

Thank you for your responses so far.

Does anyone else have any other input as to what might be causing this noise?

I'm planning to take the car to the dealer on Tuesday to try to get the car fixed. Any tips on how to protect myself from high costs at the dealership?

Thank you,

 

i would also check to make sure that the rubber splashguards in the wheelwells are buttoned up to the body... mine flaps around (with a rhythmic timing) when i start going fast...

 

So there is no way to replicate the sound with the vechile stopped? Where did you take the truck to get the oil changed?

I would lube the drivetrain, check all your bearings and bushings and then move onto the motor.

As for the dealer... there really isnt anyway to avoid a high price there.. Just fight anything that seems uneeded...

 

Does the speed of the click increase or deacrease with the RPM's of the motor or the revolution of the tires? This would help narrow down the source. Put it in neutral while your driving down the highway to see if it changes.

 

haha... funny.... mine also did that, for the longest time I thought my balljoints were goin out....

 

Don't know what the noise could be.

As far as gas being used, used the lower octane, not the mid or high. If you look in the owners manual, this is what is supposed to be used. The slower burn rate of the higher ones will do more harm in the long run (ie: deposits).

I've used BG 44K ( http://www.bgprod.com/products/fuelair.html ) with great results. I felt a difference in the drive home from the gas station after putting it in during a fillup.

 

Check out your speedo cable, it can make the weirdest noises that come from behind the dash.

It would help to know the frequency of the noises
100x/sec (almost a hiss)
10x/sec
1x/sec
???

 

Thank you for the additional responses.

To answer your great questions:
There are no mud flaps up front so I don't think that's causing it

I can't replicate the noise when the car is stopped.

The frequency of the sound doesn't seem to increase with RPMs increasing' rather the frequency of the clicking noise might be at just about a click per second. It will be something like two quick clicks that occur one per second, and then a pause of a second or two and then an additional click. That's the continula pattern of the noise.

The noise occurs when the car is in neutral too, so it's not the transmission, right?

 

so the interval of the noise is constant- about 1 per second, regardless of engine or vehicle speed, but you only hear it once you get above 50mph?

do you still have the flaps hanging down between the inner fender and the frame? any chance it is flapping in the wind, so to speak, once you get moving? like one of the fasteners that secures it to the body has come loose? or maybe it was pushed above the frame instead of hanging down on the outside of the frame like it should?

 

Is this a 5spd? I'm trying to figure out what you're saying.

When the vehicle is stopped....no noise. But, the engine is still running? Right?

And, the noise occurs with the vehicle in neutral, but the vehicle is still in motion? (This is why ask if it is a 5spd. Seems unusual to me anyone would coast in N with an automatic.)

And, the frequency of the clicking never changes relative to speed, yet only disappears at 50mph or higher. Even then, only intermittently?

And, when the motor warms it's always there?

 

/me is wondering who said 'mud flaps'

 

Is this a 5spd? I'm trying to figure out what you're saying.

No. It is not a 5spd. It is an automatic.

When the vehicle is stopped....no noise. But, the engine is still running? Right?

When the vehicle is stopped there is no knocking onice, but the engine is still running when stopped and there is still no noise.

And, the noise occurs with the vehicle in neutral, but the vehicle is still in motion? (This is why ask if it is a 5spd. Seems unusual to me anyone would coast in N with an automatic.)

The noise occurs at a speed between 30 to 50 mph. It usually is not heard initially on my drives until the engine has warmed up some and I have gone at least 50 mph. Then, once the engine has warmed, and I have gone above 50 mph, the knocking noise will start and continue at any range between 30 mph and higher.

And, the frequency of the clicking never changes relative to speed, yet only disappears at 50mph or higher. Even then, only intermittently?

Frequency of clicking doesn't vary much by speed; it might get a little faster, but not by much. It does not disappear at 50mph, it occurs at 50mph or higher.

And, when the motor warms it's always there?
It doesn't always necessarily immediately start once the engine is warm, sometimes it takes a little longer, but it always comes around, as long as I drive long enough, above at least 30mph.

Any other advice? Thank you!