blake.nemitz

ya i guess it could who knows maybe mine does but my cat is good and good o2 still. i get in and go and it warms up pretty fast so i dont worry about it. the bypass was supposed to be temporay but given the location of it under the intake i never got around to fixing it 4 years ago

rromanz

Where did you order the valve?

Up&Down

Online from Amazon. I think the company was "Car Parts Warehouse". Way cheaper than the OEM from Toyota.

VA4Runner757

Well I used to have this problem with my '02 4Runner. I have subwoofers that shake the tits off my runner and I figured that was the reason behind it. Come to find that a hanger on my exhaust system broke from offroading and the pipes were gently resting on my axle and it was vibrating. And it only occured when I was in Drive. When I would approach a stop light, i would just throw it in neutral to shut the damn noise up.

Factory hangers are rubber and I just went to a local muffler/brake shop and they welded steel hangers and i havent heard it since.

Up&Down

Duly noted. If the VSV replacement doesn't fix it then I'll check exhaust hangers and tranny mount from what I've heard. I'm finally get some jack stands this weekend (just moved from GA to ME) to replace suspension parts. I'll be able to take a look at the hangers then. Thanks for the word.

VA4Runner757

Yes sir.

Also, it could be a motor mount. If one of your motor mounts are cracked or altogether broken, then your car can pick up some rumble. Your car works harder when in Drive compared to Neutral, so when in Drive, everything will naturally shake more. So when you have a problem, when in drive, you'll notice it a lot more. It sounds certainly like metal to metal contact here. Go out and get your jack stands and hike up the back end, hop in your car, put it in drive and let the rear tires idle and listen for noise and pinpoint where its coming from. Thats the best you can do for now. If you have a general idea of the location of the sound/vibration, then you can help the mechanics.

Good luck!

Up&Down

Replaced the VSV and vibration is still there. This is driving me crazy. I checked the tranny mount and it is in fine shape.

Yesterday I went to test drive the truck after replacing all ball joints, tie rod ends, and sway bar bushings and links. As I was returning the check engine light came on. Now it idles rough at stop and hesitates and sounds like it might try to stall.

Now what?

O2 sensors? They've never been replaced. Truck has 115K.

What do y'all think?

VA4Runner757

Do you have an aftermarket cold air intake? Because yes, it could be the O2 sensor near the Catalytic Converter. I had one get dirty from mud and my dealership said that I "broke" it. So they replaced it. Go to your local car sales place like AutoZone or Advance Auto Parts and borrow a Check Engine code reader and write the codes down and look them up online. If you have a sensor that mentions that your air is too lean, then its an O2 sensor. And your car will Idle bad when an O2 sensor isnt reading properly. It'll idle low for awhile. At least mine did that.

Up&Down

No aftermarket mods of any kind.

I had a mechanic scan for OBD II codes. The one that popped up was P0170. Something about lean fuel or something.

Does anyone know what this regards as far as the idle issue. I was thinking an O2 sensor could be faulty and sending the wrong information for fuel regulation. It ain't a cheap fix.

Should I replace both of the O2 sensors?

I've cleaned that MAF, replaced air filter, checked for vacuum leaks, cleaned TB and IACV, replaced plugs, wires, cap, rotor, replaced PCV, put fuel injector cleaner through one tank of gas. I think that's it.

pendrag

Did you check the engine mounts and exhaust hangers?

Up&Down

I replaced my rear shocks this weekend and the tranny mount and exhaust hangers looked fine while I was under there. This truck was not used hard and it has spent 110K of its 115K life in a no salt zone so the undercarriage is practically mint.

I haven't checked the engine mounts but my intuition tells me they are fine. Besides, it's a 2.4L. They aren't really known for busting up engine mounts. Not enough weight or torque.

I will check for sure while I'm under there soon with an upstream O2 sensor replacement.

I did the Sea Foam clean-out. Poured 1/3 of can into intake and 2/3 of can into gas tank. Smoked like hell for a while. Idle before op temp is better.

But as usual the vibration kicks in as soon as the thermostat opens up. This makes me think O2 sensor again as there is no voltage from the O2 sensor until op temp is reached. The fuel system runs in open loop until op temp. My guess is the O2 is bad and the engine stays in open loop. Can't be good for the cat converter.

Thanks for the mounts idea check.

Keep the ideas coming. This thread will likely prove useful for a lot of people in the future.

Up&Down

Just replaced O2 sensor (upstream) and vibration still kicked in as soon as the truck reached op temp.

The tranny mount looks fine, but how do I test it? How do I test engine mounts?

I'll check these next.

The gas mileage improvement is nice from the O2 sensor replacements as well as the CEL going off.

Thanks.

Up&Down

Does anyone know how to test if the engine or tranny mounts are bad?

Could this vibration be caused by a clogged fuel filter?

If so, I'm scared to attack it. It's a 2.4L. The filter is under the intake manifold.

Does anyone know of a write-up for replacing the filter on the 2.4/2.7L engines?

rams

Hey guys, i have a 01 4Runner and have the exact same problem!
When i start it in the mornings and its warm it vibrates at red lights. But once the thermometer reaches the midway point (the normal level) it no longer shakes. During the time that it shakes the RPM is 500... is that kinda low? I put it in neutral to stop the vibration and the RPM goes up to 700.
is 500rpm low???
Sometime when it vibrates at 500rpm, i feel it vibrate stronger then weaker then stronger then weaker and i see the rpm needle move up and down just a little bit.. kinda like if the car wants to stall ..

any thoughts? maybe its the fuel pump?

pendrag

Haynes manual contains a procedure for testing the engine mounts, probably the tranny mount too, but I'm not sure. Haynes talks about replacing the fuel filter on the 2.7 also, I think.

Up&Down

I replaced the fuel filter. There is a lot of talk of this being a major PITA. Not the case. This is for the 2.4L. Just access it through the front driver's side fender well. First remove the starter. Then loosen the banjo bolts. Then loosen the bracket attachment bolts. Remove the filter with the bracket. Drain filter into a container and be awed by all the trash in there. Change filter in bracket and replace. Easy. Maybe 1.5 hours. So to all those out there afraid of the fuel filter change. Don't be. It's not a snap but totally doable for anyone. You'll need a 12mm, 14mm, 17mm, and 19mm. I had sockets and wrenchs. There was no need for stubby anything though it wouldn't hurt. So go after that fuel filter and get the improved gas mileage.

Up&Down

Had mechanic check tranny and engine mounts. No problem. All good.

They mentioned it sounded like bushings maybe. Could be fan clutch?

I changed the PS tensioner pulley for good measure.

All things the same. Vibration still there when the thermostat opens up.

I'm at a loss. I've actually run out of things to check and replace.

Please, anyone who is an expert or very experienced throw some ideas out there for more possibilities.

Up&Down

Oh, and I've read a lot of threads on replacing the PS tensioner pulley. There was a lot of talk that the parts stores all carry the AC pulley but not the PS one. I bought the AC one just to see if it works. It fit like a charm. I don't know if someone previous replaced the PS pulley with an AC one but it fits great. It was maybe a fifteen min job. I don't know if it's listed in the stores wrong or what but to all those stuck trying to press out bearings or deal with the stealership mumbo jumbo, check the AC one at the parts store. You may be surprised that it fits.

rams

could it be the fuel pump maybe?

giantjoebot

I'm having a similar problem. I already had my EGR sytem tested. Haven't tested my Charcoal canister yet, or my PCV. Also tried replacing my engine mounts with polyurethane ones, but that just made it worse, so I put the old ones back in.

I would try the transmission mount first. Especially since its only when you have it gear. Mines vibrating in neutral, but not all the time

This might sound stupid, and I have been meaning to go by the dealership to get one, but it might be your gas cap. It has a valve in it, and its part of the EVAP system. I heard that after market ones can screw things up, and you should only get an OEM gas cap.

I was also thinking that mine might be the harmonic balancer, but my pulley doesn't have any noticeable wobble, and I would rather not have to replace that unless I have to. Seem like a pain.

Good luck. If I figure mine out I'll let you know, and I'll watch this thread from possible solutions to my own problem.