22re idle problems

When I hit the throttle and let the engine return to idle the rpms drop below normal and almost stalls. It then fluctuates for a few seconds before settling on a constant rpm. Does anyone have an ideas what the problem could be?

 

Do you have the brake pedal pressed when this happens? If so, does it still do it when the brakes are NOT pressed?
What do you have the idle set to? Anything like 1000 RPM or a little higher?
Have you checked the idle adjust screw's o-ring? Did you try inspecting it? Screw the idle adjust screw all the way to the bottom, counting the turns it takes, the screw it all the way out and check the o-ring. O-rings to fit are readily available at almost any auto parts or hardware stores. I've found that a thin layer of Vaseline on o-rings, or any rubber seal, will make them last a lot longer, and seal better. Once it's known good, put the screw back in, screwing it all the way to the bottom, then back it out to where it was when you started. Good place to start from. Adjust the idle to 800 RPM, with the engine good and warmed up.
Make sure you use a external tachometer, not one that came with, or is part-n-parcel of the vehicle.

Have you checked and adjusted the TPS IAW the FSM? Have you checked the ohm readings of the VAFM IAW the FSM?
Are the any cracks or other leaks in the big tube between the VAFM and the TB? Especially at the two ends where it turns the corners? Pull it off and look into them while you flex them around. Any light coming in anywhere when you do this?
Have you checked the tube between the Air Valve and the TB? Any leaks or cracks?
Heck, have you checked ALL the vacuum lines? Any leaks or cracks anywhere? Vacuum line is cheap and easy to replace, after all.
Have you tried lubing the TPS to make certain its movement isn't restricted in any way?
Have you checked and set the timing correctly?

Just trying to think of any possibilities. I'm sure the true geniuses on the forum will have better ideas.
Pat☺

 

It does it with or without the brake pedal depressed, I inspected the idle screw and replaced the o-ring. With the truck warm I set the idle down to 800 using an external tach but it still does it. Also tried setting the idle with the jumper in. I adjusted the tps to spec but havent checked the vafm. No cracks in the air tube and vaccuum lines all look good. I recently replaced the timing chain and set it to 5 degrees btdc with jumper in. I also replaced cap and rotor, wires, fuel injectors, fuel filter, water pump, alternator, air filter, and o2 sensor. The exhaust also rusted off at the muffler, not sure if thatbwould affect anything. I currently have the idle set around 1000 so that when it drops it doesnt stall.

 

Check your dashpot.

 

It dampens the closing of the throttle body like it should, not sure how to tell if it is bad.

 

There's a test procedure in the FSM, actually.
Easy, quick test, though: Open the throttle ways, let it go so it snaps back toword closed. The dashpot should allow it to close most of the way unrestricted, and when it gets close to closed, it should slow it down. Still allow it to close, just much slower. You can easily see where the piece that the throttle cable attaches to contacts the end of the DP on the way to closed. Once it hits the dashpot, it should still go to closed, but you can see the DP retracting slowly, thus slowing the throttle plate.
Hope this helps a little...
Pat☺

 

After some testing I discovered that the idle doesnt fluctuate if I remove the oilcap.

 

The big cap in the valve cover where you add oil, like after you've changed the oil?

If removing THAT causes idle fluctuations to stop, it sounds like there's pressure building up under the valve cover. Try replacing the PCV valve. If it's clogged up, not opening somehow, it could cause the pressure build up.
Grab a cheapie at an auto parts store, just to test. Chances are, you'll need the gasket for it too. If that proves to be the trouble, then you can go ahead and order a new OEM from Rock Auto, or wherever. If it's not, you can put the original back in. If you put the original back in, though, it's a good idea to clean it out real well. A few squirts of carb cleaner will do it nicely.
No matter what, if you go to pull the PCV out, the gasket will probably be bad. They tend to get hard and brittle pretty fast once installed. When you try to remove the PCV, the gasket will probably crack and fall apart. You'll have to pull the chunks out. I use needle nose pliers. Be careful, though. If chunks of it fall down inside, you'll need to pull the valve cover off to get them out.
SO, if you haven't changed the valve cover gasket in a while, say a few years, and you have to pull the valve cover off, you'll need a new gasket set for it. You can get a valve cover gasket set for about $20.00. While you're in there, it'd be a very, very good idea to set the valve lash. That's a pretty important bit of maintenance.
There's an excellent procedure in the FSM on how to do it. It's not difficult, and takes but a short time to do. Honestly, the longest part of doing all that is putting all the vacuum lines, and VSV's, back on
Make sure you put the valve cover gasket in correctly. It will be shaped slightly like a T. The leg of the T goes into the channel on the valve cover, and the cross-bar sits against the head. Make sure the channel, and mating surface for it on the head, are both good and clean before installation. Especially where the half moons sit in the head.
If you don't make sure the channels for the half-moons on the head aren't real clean, or if you don't clean the old RTV off before you put new on, they'll leak. They be a frustrating leak to chase down too. Particularly the one in the back.
A little trick I found, that makes putting the valve cover back on, with the new gasket in it, easier, is to stick the gasket to cover. Take a small dab of grease, like a good moly-b type, something thick, and put it into the corners, and a couple dabs along the straights of the cover's channel. It will hold the gasket into the channel for you while you put it on.
Another thing, is that the new gaskets for the acorn nuts that hold the cover on can be a little too big sometimes, making the cover sit too high to get the nuts on. Take and put 3 of the old ones on, tighten them down good, and then put a new one on the 4th bolt. That will pull the cover down enough that you can start the 4th nut. Then, once you've got the 4th tight, replace one of the others. Opposite corner is best. You can do it that way for all 4 of them.
Good luck!
Pat☺

 

Thanks Pat, I ordered a new pcv and gasket on rockauto since I was already ordering other parts. Hopefully this fixes the problem. For now I have the breather hose disconnected and it seems to run fine. I did the valve cover gasket and set the valve lash already but one of the valve cover nuts has a slight knock to it (front of engine passenger side). I the other nuts dont seem to have the same knock and the valve cover also doesnt seem to have a knock to it. I thought it was the rocker arms hitting the valve cover but even if I loosen the valve cover all the way, that nut still has a knock to it.

 

These engines are known to have knocks, rattles, etc. Usually the valves. No matter how you adjust them, you're going to have small valve rattles. Presuming you adjust them correctly. It's just the way these engines are. Nothing to be done about them. It's just the way it is. They rattle.

It's not the valve cover nuts, per se. It's the valves, timing chain, rocker arms, whatever, but the external acorn nuts just hold the valve cover on. Once they're installed, with the gaskets, they can't knock. Just a nut on a bolt, with a rubber and metal gasket on it. No way to move, so no way to knock. It may SOUND like it's coming from that area, but that's all it is.

While you had the valve cover off, did you take a good look down the galley where the timing chain runs? All you need a decently bright flashlight. Check to make sure the chain guides are still in good shape? Chain is properly tensioned? I have really big hands, so I have a lot of trouble reaching down to check the tension, but I just use a long screwdriver to do it.
There isn't a replacement interval on the timing chain, per se. Just check it real good any time you have the valve cover off. It will pay off.
Honestly, the timing chains, guides, etc, usually last around 100K but after that, beware. If the guides are broken, you'll need to drop the oil pan to get all the chunks of guide out. Not real fun, but necessary.
I just had my timing chain, guides, and tensioner replaced on my 4Runner last year, at about 175K miles, but my pickup's timing chain, guides, etc, is still good at 325K. That pickup amazes me all the time.
Of course, I've had to replace the pickup's oil pump gasket several times, like 6 or 7, but only twice on the 4Runner.
Sooner or later I'm going to need to get the crankshaft oil seal modification kit for them both. They both have grooves worn in the crankshaft where the front oil seal rides.

Anywho, glad you're getting that thing going good. I wish you great enjoyment of it
Pat

 

I recently replaced the timing chain and guides, this engine is just giving me problems one after another. Previous owner did not do much maintenance so everything was pretty much bad. Im debating pulling the motor and either rebuilding or swapping. Thanks for all the help Pat, hopefully I can get it running like new again

 

Just bear in mind, even new, after just a few miles, these 22R type engines still wound up with the rattle. It's just...the way they are.

I do wish you the very best, though!
Pat☺

 

If you tighten the valve cover nuts too tight it pulls on the rocker rails adjusting your valve lash and that can be making the noise.

 

I had a 93 4Runner with a 22RE and it was as quiet as a Camry. No 22R/E I've had before or after has ever been so quiet. If that 4Runner wasn't green I might have kept it forever.