Tempeboy

Hello, I have received a lot of help through the great contributors here at Yotatech and all the advise has solved many of my problems.

Now I find myself back here in the forums asking for help/advise once again

OK, I have a 91 4runner, 3vze, automatic and about a week ago I noticed that when I start it up it starts shaking ALMOST like it wants to bog down but it stays idle at 700 (around 1000-1200 in Park)

If I am at a stop light, I can feel the shaking start again, but the idle stays right around 700 and the needle only slightly moves with the shaking. When I accelerate, it seems to hesitate a little bit, but then drives fine.

Sometimes at the stop lights the shaking is worse, sometimes not so much. I suspect this is a fuel problem such as Injectors. My fuel pump was replaced about 3 months ago along with the timing belt, and my plugs and cables were replaced about 11 months ago.

Any ideas-comments-suggestions, as always, is greatly appreciated.
THANK YOU!!

Jay351

Are your motor mounts good?

DilutedImage

That's the first place I'd look.

Tempeboy

I will check the mounts, but I am not sure they would contribute to the hesitation in the accelerating from the stop light.

Guardian_Saint

I have this hesitating issue awhile back after my timing belt replacement, after investigating, I found one tube that connect to the power steering was off so I plug it back in then VROOOM! back at 100% normal. Also when you said that you stop at the red light it drop to 700 and when you accelerate up it went back to normal, I have this problem too, it was my brake booster, it went bad. To check your, you can press the brake and see if it drop idle and hear air is leaking through the firewall, if it does all that then its the brake booster.

b.miller123

I know you said that the plugs and wires were replaced 11 months ago, but I would make sure that your wires aren't touching anything hot, especially on the passenger side, if they are in contact with any of the egr piping, they will melt through very quickly, and you might not even notice the difference when one of them does it, but as soon as two of the wires are being grounded (and your running on 4 cyl, with 3 on one side and one on the other!) trust me, you'll know, you're idle will be rough (bouncy) and you will definately notice a drop in power
There are supposed to be little clips by the exhaust manifold holding them away from everything, but they are about as tough as the clips for the grill (if you've ever taken it off you know what I mean)

Jay351

aint that the friggin truth! I think I have 2 left on my grill

DilutedImage

Sorry, I missed the part about the hesitation. It sounds like it may be a misfire. As others have stated, check all your plugs and wires.

Another thing to check for is vacuum leaks. I noticed similar behavior in my father-in-law's Mustang recently, and it turned out to be a vacuum leak. The leak was past a vacuum switch (I forget which one), so the problem only occurred intermittently.

Jay351

When was the fuel filter last replaced?

Toyota claims it never has to be changed but its recomended if you have over 80,000miles on it.

b.miller123

I think mine is only held in by the corner lights

Tempeboy

Thanks for all the input so far guys!!

OK, the plug wires look fine so I dont think thats the issue.

This morning I was driving it to work and the idling was a bit rough while stopped. Also while i was getting up to around 50mph it just hesitated for a moment and then kicked in. On the way back from work it drove real smooth the idle was slightly less rough but still noticeable at the stop lights.

Dead spark plug?

Targetnut

First check the coolant level, With the history these engines have with head gaskets, It would be a good first check.

If the coolant level is still OK, inspect the spark plugs. are they still in good shape, Or are they fouled? Black and sooty? Look closely at the porcelain insulator for cracks or carbon tracking. Look at the insulator around the center electrode for cracks.

If that is OK, check for air or vacuum leaks.

Check the EGR operation. Tap on the EGR valve with a screwdriver handle while it is idling, does it smooth out? If so the EGR is sticking on.

Check the VF voltage in the diagnostic connector under the hood.

You could also check the fuel pressure and delivery volume. Although these would be less likely to cause a problem at idle.

Tempeboy

alright coolant level is fine, tapping egr valve doesnt smooth it out

Its getting worse, the rpms do not move around when I at a stop light, but it shakes like its misfiring or something.

Also now when i hit the gas it just jerks like its trying to go, but acts like its not getting any gas, or just sucking up air. then it will surge, the rpms start going up and down and around 45-50 it wont really go any faster.

EDIT:I can actually feel the truck get a little power and then lose a little power holding it steady at 30 mph. The rpms go up a little and down a little, really inconsistent.

Jay351

Have you checked for any codes?

you can somtimes have some but not enough to trigger the check engine light

881stGenRunner

check your catalytic converter, i had a similar problem with mine and it turned out to be the Cat

Tempeboy

No I haven't, can they pull them up at like a Midas or is there something I can buy to do it myself. (I only say Midas because its like half a block from me)

881stGenRunner

its very easy to take off, just 2 14mm bolts on both flanges and voila its off. you will need two wrenches or a ratchet and a wrench since it uses a bolt and nut.

Jay351

If you're talking about pulling codes you can do it yourself.


Get a paper clip or a peice of wire. Open the little grey box by your battery named "diagnostic" Then jump the e1 and Te1 connectors.

Go into the truck, turn the key to start and count the flashes of the check engine light

have a pen and paper ready.

constant flashing means there are no codes.

WCorbett

This happend to me very recently. I fixed in with new plugs, wires, and distributor cap and rotar. what happend is the plug wire was worn out and was grounding out to the exhaust so one piston wasnt fireing.

aaronk

My 22RE had very similar systems and a valve adjustment solved the problem.

At a stop light the engine would physically shake the car enough that you could feel it in the cab. Rev it up to 1500rpm and it would smooth out. While it was shaking the RPM's didn't really budge much at all. My exhaust also smelled really rich.

Anyways, just something else to look at if you haven't had a valve adjustment in a while.