School Me!!!!

Did you pull the spark plugs and check them for that nice coffee color? I had a misfire in one cylinder in a Dodge and it turned out to be a hairline manufacturing defect that was allowing coolant seepage into the cylinder, but it was more of an idling problem than an under load problem.

As for live code data, if you're looking at fuel use and combustion efficiency, I think you want to check the voltage data from the o2 sensors and the long term fuel trim numbers. Voltage for upstream o2 should bounce between about .2 and .8 I think, and downstream should be more steady somewhere in between. LTFTs should be in the single digit range.

If the injector is working the misfire would allow raw gas out of the exhaust. You would see high o2 voltages and negative LTFTs in the teens, I think.
 
Spark plugs don't have any color at all they are brand new dual NGK's. thanks for info on live data, will be checking compression later tonight, also checking brand of O2 sensors, plug wires, and then do test drive to check live data. Those live code readers are a must have for this type of problem! Like I said I want to actually see a problem before I just throw parts at it or just poke and hope I get it fixed, otherwise nothing is gained but $ lost! ya know?
 
Ok compression test completed
#1- 200 psi no drop. #2- 198 psi no drop
#3- 200 psi no drop. #4- 190 psi no drop
#5- 203 psi no drop. #6- 205 psi no drop
Spark plugs are: Autolite premium 5mm silicone suppression cable SAE Class E... Any good?...
O2 sensor status:
#1 is a toyota denso # 89465-35380
idle 850 Rpm constant fluctuation .03-.8v
Revved to 1800 rpm steady .855v

#2 is a toyota denso's 89465-3550
Idle at 850 RPM .07v
Revved To 1800 RPM flux .225v-.115v let off goes to .735v

MAF reading idle- .5 lb/m
1800 RPM- 1.16ib/m

Are these spark wires any good, thank god my cylinders are holding good pressure was sweating that., let me know your thoughts I'm still getting #2 misfire, thanks!
 
I usually like to reserve Autolite for Ford, even though they can work in Chevy as well as in Jeep applications.

Ditch the wires and get some NGK te66s (4412) for about $30. How strong is the existing spark out of plug #2 in compared to others? At least the engine is healthy.

Also, does your 4runner have dual cats by chance? The 02 numbers are not interchangeable.
 
No just have single cat, also did vacuum test pulling steady 19.5 inHg according to specs that healthy as well, coolant sensor at 180deg reading 331ohm looking at egr now prob def get wires bout only thing left
 
Belay my last, so going through shop manual said to check egr, said if you hook up vacuum pump should idle rough or stall, so I was going to use intake manifold to test this theory, when I disconnect the small hose from the side of the component mounted under the throttle position sensor, idle rpm when up but sounded great, smooth with no miss, before at running temp I could go 1/2 mile and throw P0302, after disconnecting that small tube I drove for at least 20 miles no probs and had good reaction (hardly any lag) good acceleration and no misses on any cylinder. So question what is that thing, what does it do and is that small tube supposed to have a hard vacuum to it? Say about 18-20inHg
 
Ok so little confusing on last couple posts, sorry was 2 am or so, yes I do not have an egr valve after closer look in book it was describing checking egr on 4cyl engine. Will post pic when I get home, site will not let me upload from my phone. I went to advance auto (for what that's worth) and they couldn't tell me what the questionable part is either. But like I said is mounted to throttle body on backside nearest windshield, mounted by two Phillips head screws directly under throttle position sensor, a small vacuum hose connects to barb on part then runs over to driver side on backside of plenum to another barb. Idles kinda poor when warm, but disconnect and idle rpm increases but can tell a def difference in operation of engine, doesn't sound like its choking. Pics to come later
 
Nope thats mounted under throttle body with two coolant hoses and another hose on bottom, this hose is pushed on from top down prob 1/8-1/4" hose, good thing is I think I eliminated all the fuel injection system and lies in the vacuum system somewhere, I mean I have a good vacuum just don't know if its in any of the vacuum valves or sensors, that's where I'll be looking today
 
Ok this is the part in question anyone know what it is?
 

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Cheap2000SR5 said:
Ok this is the part in question anyone know what it is?
Click to expand...

That's the throttle-opener thingy only found on 5-speed V6's. If you leave that hose off, it will idle way high (~1300RPM) as it holds the throttle plate slightly open when vacuum is removed. Why 5-speeds need it, I have no idea.
 
Ok so since last post, I've replaced the coolant temperature sensor, and ditched the Autolite spark plugs with the NGK's, took on a test drive and no issues what so ever, drives and idles, acceleration, and response is incredible, have never seen this thing run so well. Will update is it starts to act up again. Now that is is running good time to move on to the appearance and get this turd polished lol thanks for all the advice, help, and direction from all those that helped me break into the world on T4R troubleshooting. Thanks guys much appreciated!!
 
Good to hear. For all the autos I've worked on in twenty years, this 4runner can be picky on what is used in it. OEM, or OEM usually works best.
 
Cheap2000SR5 said:
Mine is an automatic so what does that mean?
Click to expand...

Hmmmm, either
1. I was wrong, or
2. Somebody swapped in a new TB from a 5-speed.

My info wasn't hard, just another poster, so if I was wrong I do apologize. Anyway, that's what it does. That I'm sure of, because I have one.

Here is the thread that led me to think that. That diaphragm thingy is what connects to the vacuum pipe in the thread. So I guess we just don't know what models use that thing and which do not.
http://www.toyota-4runner.org/3rd-gen-t4rs/163386-know-where-goes.html

Anybody want to clear this up for us?
 
Last edited:
Cheap2000SR5 said:
Ok compression test completed
#1- 200 psi no drop. #2- 198 psi no drop
#3- 200 psi no drop. #4- 190 psi no drop
#5- 203 psi no drop. #6- 205 psi no drop
Spark plugs are: Autolite premium 5mm silicone suppression cable SAE Class E... Any good?...
O2 sensor status:
#1 is a toyota denso # 89465-35380
idle 850 Rpm constant fluctuation .03-.8v
Revved to 1800 rpm steady .855v

#2 is a toyota denso's 89465-3550
Idle at 850 RPM .07v
Revved To 1800 RPM flux .225v-.115v let off goes to .735v

MAF reading idle- .5 lb/m
1800 RPM- 1.16ib/m

Are these spark wires any good, thank god my cylinders are holding good pressure was sweating that., let me know your thoughts I'm still getting #2 misfire, thanks!
Click to expand...

Hey. I hope you are still around. You've had lots of time to sort this out. But, in case someone else searches the same thing I did, I will comment on item #1. That is how that kind of sensor works. it looks like saw tooth pattern on a scanner. if it's fairly evenly distributed up and down the scale it is doing its job. If the pattern locates toward the top of the scale with a bottom area that it doesn't extend to, it's either rich, or lean, I forget which.

Same thing if the pattern starts at the bottom of a graph, but doesn't make it toward the top, it's either lean or rich, I forget which.

Another item is that this specific sensor is for federal emission regulations vehicles and NOT for kali regs. It took me months to puzzle all this out, I hope it helps someone else. It does not help that the easily obtainable digitized factory service manual is 2002 year, and a LOT of the emission stuff in it does not apply to 1999 4runner federales.

:fish2:


Ciao Runners
 
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