4runner stutters

Marsh99

Marsh99

Lover of all things Toyota
Location
Mantua UT
so my runner is still running weird... What it is doing is only under a load( going up hill or pulling hard in a gear) around 2500- 3000 rpm it is stuttering, but can be cured temporarily with a rev. It is inconstant and can not be replicated with out moving. No check engine light...
so far I have:

  • New Plugs
  • New wires
  • New distributor rotor and cap
  • New fuel pump and filter
  • new o2 sensor
  • cleaned and soldered the injector wires
  • checked vacuum lines
  • checked fuses
  • thought and searched a lot ... tried of throwing parts at it:ugh:
any other thoughts?
thanks
 
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Is your Tach erratic?

Coil and ignitor possibly...these were the same mild symptoms my '87 had. I continued to get worse as the dielectric in the coil pack degraded.

Mine would only stutter under load above 3k, no codes. Eventually it became undriveable above 30mph and began backfiring.

You might also checlk the air gap of the pickup sensor under the distributor cap.

After everyting you've done, a check of the TPS would also be helpful.
 
SLC97SR5 said:
Is your Tach erratic?

Coil and ignitor possibly...these were the same mild symptoms my '87 had. I continued to get worse as the dielectric in the coil pack degraded.

Mine would only stutter under load above 3k, no codes. Eventually it became undriveable above 30mph and began backfiring.

You might also checlk the air gap of the pickup sensor under the distributor cap.

After everyting you've done, a check of the TPS would also be helpful.
Click to expand...

yes the tach goes erratic. I will check the air gap.
 
ok so i did a bunch of research to day this it what I found;
22re toyota's have 2 types of check engine problems;

  1. check engine light turns on and stays on
  2. soft problem light flashes on and shuts off
I found out the codes don't clear until you manually clear them.

you check them by jumping the diagnosis box and watch how many times check engine light flashes after a minute or so.
http://www.4crawler.com/4x4/CheapTricks/index.shtml#TimingCheckConnector

on a 85 the diagnosis box is the the small plug on drivers side fender.

So I jumper mine and guess what. 7 flashes
http://www.4crawler.com/4x4/CheapTricks/Images/85diagnosticcodes.gif

Bad TPS or ECU
So I figure I can start here for now...

I am happy I figured this all out but I wish I could have done it faster.. Next time I will know all these tricks . I hope this helps others.
 
I'm glad you found that, Roger Brown really pioneered/published the cheap troubleshooting/workarounds. He is very well known, I just figure everyone knows about his site:D

Before you swap an ECU, check the connectors for moisture on the passenger kick panel, a common problem is corrosion between the body of the 4Runner and the case of the ECU.

The TPS's are somewhat problematic but the erratic tach suggests a discrete is being dropped from either the ECU or the Coil/Igniter. There are resistance tests to help rule out the coil but they are based at room temp and as the coil fires it builds heat which is when mine exhibited symptoms...it tested like new at room temp.

While you are checking the ECU it's easy to remove it from the truck and open it up via the 4-5 phillips screws to check for corrosion or burned PCB/components.

Good luck!
 
SLC97SR5 said:
I'm glad you found that, Roger Brown really pioneered/published the cheap troubleshooting/workarounds. He is very well known, I just figure everyone knows about his site:D

Before you swap an ECU, check the connectors for moisture on the passenger kick panel, a common problem is corrosion between the body of the 4Runner and the case of the ECU.

The TPS's are somewhat problematic but the erratic tach suggests a discrete is being dropped from either the ECU or the Coil/Igniter. There are resistance tests to help rule out the coil but they are based at room temp and as the coil fires it builds heat which is when mine exhibited symptoms...it tested like new at room temp.

While you are checking the ECU it's easy to remove it from the truck and open it up via the 4-5 phillips screws to check for corrosion or burned PCB/components.

Good luck!
Click to expand...


I will check the ECU. My body doesn't have any corrosion on it. I hope it is the TPS, I broke mine, after I pulled it out I dropped it and cracked the case. I order one today it should be here in a couple of days.
 
my ecu board looks good, no burn marks and it is as clean as a whistle. So I hope it is the TPS...
 
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I would vote TPS from what you are saying, the only other thing that it could be is the MASS. Mine does the same thing but not under load and it is random, wont happen for like 7 months and then it will happen again and the Check engine light comes on sometimes when it is happening. I talked with guys at weber that know toyotas inside and out and they said the TPS or MASS is the cause 90 percent of the time so good luck
 
Installed TPS and it stopped throwing that code but did not fix the problem, but my buddy leorn let me borrow his 82 supra AFM. I think that is the ticket!! it is sweet and adds some power. I am going to drive with for the weekend to make sure... but I am crossing my fingers
 
also I found out my o2 sensor is in the wrong spot it needs to be mounted on the manifold and it is after the cast currently so it not getting hot enough. I think i might break down and go get a custom exhaust built.
 
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