Help 1996 4Runner 3.4 Engine hesitation, no power over 2000 rpm

[ElTaco2]

A340F transmissions are pretty universal for all the 3rd gen years. A 99 limited should be a direct fit into a 97.

There are some differences in valve bodies but I’m pretty sure the valve body in 99 is the same as the 97.

That's great!! Thanks!!

 

[werminghausen]

My wire set from autozone came with wires and boots. Most sets do. I bought the autozone set because I wanted a mag core set and they stopped selling the Bosch brand I always bought.


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I bought a set of wires ( I think for 3 plugs, #1, #3 and #5? ) and down at the long end there are indeed boots at the bottom sealing the spark plug. The other 3 plugs/boots are on the coils I guess. I wonder how the rubber boots will look at the coils. Coils seem to be old and original with Toyota labels I think.

I am waiting for the plugs and new wire set for install. I wonder if people would recommend changing coils (Delphi brand)
Martin

 

[19963.4lsr5]

I bought a set of wires ( I think for 3 plugs, #1, #3 and #5? ) and down at the long end there are indeed boots at the bottom sealing the spark plug. The other 3 plugs/boots are on the coils I guess. I wonder how the rubber boots will look at the coils. Coils seem to be old and original with Toyota labels I think.



I am waiting for the plugs and new wire set for install. I wonder if people would recommend changing coils (Delphi brand)

Martin

If you didn't get boots for the coils you should order them and do it all.


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[werminghausen]

Thanks, as you know I have the new NGK ignition wire set ,
for the coils do I need

** Direct Ignition Coil Boot-Coil on Plug Boot NGK fits 95-04 Toyota Tacoma 3.4L-V6
Part# 58931


Please confirm that these are the boots that need replacement for the coil at cylinders #2,#4 and #6? (maybe I have the cylinder numbers confused, forgive me)

Martin

 

[19963.4lsr5]

I thought the NGK set came with the boots for the coils too.


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[werminghausen]

I thought the NGK set came with the boots for the coils too.


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Thanks, yes of course the NGK wore set comes with new boots, all agreed.
My question however is about changing the boots on the 3 coils, which I suspect highly as a leak point. Again my question: are the boots on the Toyota coils exchangeable? And if yes is part # 58931 correct to order?
If not exchangeable i‘d order new coils (Delphi brand, set of 3 for $150)
Martin

 

[19963.4lsr5]

Thanks, yes of course the NGK wore set comes with new boots, all agreed.

My question however is about changing the boots on the 3 coils, which I suspect highly as a leak point. Again my question: are the boots on the Toyota coils exchangeable? And if yes is part # 58931 correct to order?

If not exchangeable i‘d order new coils (Delphi brand, set of 3 for $150)

Martin

They will mount to your existing coils.


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[werminghausen]

Thanks 19963.4

I ordered 3 coil boots (NGK brand).
I already received the NGK wire set and
6 Denso spark plugs K16TR11

What is the gap spec for the spark plugs for checking? Could be 0.044" and they should be pre-gapped already?
If I receive the new coil boots in time I'll do the swap coming Saturday.
Should be done in 2 hours I hope.

Then the moment of truth will come... rev-ing the engine. Does the engine work now... Yes or No?

Martin

 

[19963.4lsr5]

You shouldn’t regap the plugs.


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[werminghausen]

You shouldn’t regap the plugs.


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Why? This is only checking the gaps and correct to proper gap if not to spec ?
I just want to understand where you are coming from.
Martin

 

[19963.4lsr5]

Why? This is only checking the gaps and correct to proper gap if not to spec ?

I just want to understand where you are coming from.

Martin

It’s a precise fit the way the ground side gap arms are shaped. I’ve done it but it’s not recommended. You can check for sure. I put a set of these in my Saturn and re gapped them to Saturn spec. Then I found a heat range 6 in a much closer gap.


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[werminghausen]

Bummer: This morning I was testing the engine again and to my surprise the
hesitation and sputtering above 4K has gone away entirely!

I think this came as a surprise... I also think this is confirming the theory that
the problem is/was wetness /moisture which went away slowly?



I am close installing new spark plugs, wire set and coil boots. I have all parts together now.
Unfortunately it may remain a secret which parts was the primary problem.

Martin

 

[werminghausen]

oopps .... one thread tripped at coil cylinder 5... It's a M6 bolt, need to fix this but I don't have a helicoil M6.... grrr.
Not sure if this means something ... the 3 boots I am looking at look all fine and the old spark plugs so far as well. I have not been at the left cylinder bank 2/4/6 yet.

Martin

 

[werminghausen]

So I am through now.
I fixed the tripped M6 thread by drilling 8.5 and cut a M10 thread. Then I turned a sleeve in brass with outer M10 and inner M6... it worked.

The left bay side spark plug wires were fine... all boots seemed tight, no sign of oxidation inside.
The ignition wires are in good shape (well only 2 or 3 years old).
I doubt that there was a problem. If there was the problem will show up again.

The right bank with the coils could have had a problem at one or more top connectors to ignition wires (ignition wires to be clicked in place) In this connection I found some oxidation. Splashing water could have reached that area because it is accessible by water directly. But if there would be some moisture trapped causing sputtering... then it probably would have dried out quickly.

Again I installed new spark plug and new coil boots... left the ignition wires in place. Old spark plugs (maybe 15K miles) did not look bad at all. Also the old
coil boots were still vert flexible and no sign of deterioration.

I used No-OX-ID on all connections to prevent oxidation on aluminum.

Unfortunately I am not sure now what the problem really was.
Any thoughts?


Martin

 

[werminghausen]

After one week + week of happy driving I am still wondering what the hesitation was and i‘d appreciate your input. This is a fair inquiry after having spent couple hundreds and time into a problem that was not solved by the money and effort but by just drying out?
At least the problem has gone away and thanks to recommendations I have a new catalytic converter.
Isn‘t it amazing that seemingly none of the OBD codes and problem could be found as a clear problem?
Could it be that the system‘s Computer did not detect the problem at all?

If a moisture problem is common causing severe hesitation and drivability issues why did this issue not come up more clearly . No blame to anyone I am just curious.
Martin

 

[gamefreakgc]

Moisture can definitely cause issues if it's in places it shouldn't be. Unfortunately these sort of things can be hard to find. I had an older Toyota that would lose all power for about 1/4 of a second and then lurch back to life. Changed out a bunch of ignition and charging items and never fixed the problem. But it went on to cross 300k miles, so I guess it wasn't a big deal.

 

[werminghausen]

After a couple of months nothing bad really happened again.
Only once it stated hesitating at higher rev (was around 4K I think) and this went away... so I am hoping I'll get through New England winter here.

Thanks for all your answers. Martin