At my wits end with this 3.4... HELP.

Ok.. I know it's been a few days but I finally got a scanner that reads live data.. I took a video of it so people could see what was going on but it ended up being too long for you tube.. From this link Interpreting Generic OBD-II Scan Data » OBD-II Resource , I seems that I've got a vac leak somewhere the way my SHRTFT is ranging from -14.1 to +7.8 and the LNGFT is stayin' around +2 to +5.. What ya think?..
 
Well, I'm still stumped.. It's been a month since I've last posted anything to this thread due to "trying to figure this thing out".. It's running great except for this one issue of "purging"... You can't tell it from lookin' at the tach but with the scanner hooked up & using live data, the RPM's are climbing from 650ish to 710ish in a smooth rhythmic action, as if I were lightly feathering the gas pedal. It seems to only do it under 2200 rpm & after that, it's all good.. The whaaaa, whaaaa, whaaaa, whaaaa at idle or just taking off is driving me crazy.. Since this started, I have replaced the following with NEW: Exhaust (from mani back) 2 cats, muffler, 2 Denso O2's, battery, TPS, timing belt, wtr pump, thermostat, NGK plugs/wires, coil packs, air fltr, oil, all vacuum lines (I think), & radiator.. I have taken the TB off & cleaned it, cleaned the IAC valve (and checked resistance) it's good, switched & checked the Char Canister & the VSV (everything does what it's suppose to).. All timing marks were lined up. Checked resistance on CPS, good..I can't figure out what I'm missin'... There's no CEL or codes.. Like I said, it runs great, EXCEPT for this one issue.. I'm down to either takin' it to a dealership, or becoming very religious & start prayin' the big man can help (the cheaper of the two)..
 
In my opinion it sounds like a vacuum leak to me as others have previously stated. As ypu rev the engine up the issue goes away because so does engine vacuum. Any air leak after your MAF is unmetered air flow or air that is getting into the engine that the ecu does not see which it will try and compensate for thus causing the bouncy idle. carb spray can sometimes help you locate a leak but not always. It could be a vacuum line, any intake manifold or throttle body gasket. A cracked intake tube, seal for your iacv, brake booster or vacuum line to your booster. Between the booster and master cylinder is a seal that can cause a vacuum leak. Not saying these are common but at this point i would not rule anything out. My advice to you would be to pay the diagnosis fee and go from there. Hope you get it resolved.
 
Broke down & took it to a Diagnostic center... They called about 4hrs later, & said they could NOT find anything.. Gave the OK for them to do a $70 "Smoke test" & and hr later, was told there was NO vacuum leaks.. I did, however, change out the MAF sensor before I took it to 'em & the wife said it didn't act as bad as before, but the "RPM surge" was still there.. The owner of the place said all he could figure, it's just something that happens with the amount of mileage on the motor.. (186, somethin).. Don't exactly agree with him but, if they couldn't find anything, I'm probably not going to either.. I plan on changing out the injectors and gettin' a NEW IAC valve, since damn near everything else is new under the hood, just to even it all out.. Thanks for all the post on what ya'll thought.. It helped me to know what to look for.. Since last Oct, I've learned alot about this Rnr and feel much better raisin' the hood.. If I get a chance, I'd like to take a short video of it & post here so all can hear what it's doin'.. Maybe it'll spark an epiphany..
 
hey man good luck! i myself am about to pull my hair out with my t4r as well, im going to order some injectors, my symptoms arent the same as yours (i have a loss of power and a misfire in cylinder 4 and just running poorly, i also changed the plugs/wires coil pack etc no avail) but anyways who knows it could be the japanese version of a mopar mystery! lol
 
hondafmx1000 said:
hey man good luck! i myself am about to pull my hair out with my t4r as well, im going to order some injectors, my symptoms arent the same as yours (i have a loss of power and a misfire in cylinder 4 and just running poorly, i also changed the plugs/wires coil pack etc no avail) but anyways who knows it could be the japanese version of a mopar mystery! lol
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thats ironic. have my sons 98 sr5 in the shop. throwing CEL and saying #4 cyl. replaced plug wires, no help. bad injector,fixed. now dam thing will not idle. almost stalls when you come to a stop. Aaaahhhhhhh frustration !!!!
 
A.Wilson013 said:
For shoots and giggles, test the resistance on your fuel pump...

It's page 3 of this link...

http://www.ncttora.com/fsm/2003/Repair_Manual/03tacoma/sf5vzfe/fuepum/ovi.pdf
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Hey Wilson.. Thanks for the "shoots & giggles" tip... It never occurred to me to check this...
This could be it..!! (fingers crossed)... Checked the resistance and it was well above the specs.. Guess'n I got a wknd project lined up... Of course Toyota couldn't make the "service" hole a lil bit bigger than the size of the pump.. Anybody have any idea what kind of job takin' the tank out is??
 
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Fuel pump great idea and while we are there when was the last time a fuel filter was swapped out? I do mine about every 100K, so coming up on my 3rd sheesh the miles just fly by. I never had a weird idle like this but it defineitely sound fuel related. Especially since you've nearly ruled out everything else.

Aaron
 
haven't read this thread entirely but I did have a similar incident like this where I tried all these fixes. It was on a 2JZ-GE motor. The pulley had seized and caused the timing belt to skip a few teeth. Not saying it's that but it may be worth a look. Best of luck...
 
xcmountain80 said:
Fuel pump great idea and while we are there when was the last time a fuel filter was swapped out? I do mine about every 100K, so coming up on my 3rd sheesh the miles just fly by. I never had a weird idle like this but it defineitely sound fuel related. Especially since you've nearly ruled out everything else.

Aaron
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The fuel fltr was one of the things on the list that got updated within the last 3 months... Probably the first time it's been changed.. I'm sittin' on 186,???.. That is one of the easiest items to overlook..
 
TFJ-4runner said:
haven't read this thread entirely but I did have a similar incident like this where I tried all these fixes. It was on a 2JZ-GE motor. The pulley had seized and caused the timing belt to skip a few teeth. Not saying it's that but it may be worth a look. Best of luck...
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Hey TFJ.. The TB/WP was done on New Years Eve.. Everything was still lined up good.. That would suk to have a pulley seize up on you.. Skippin' a few teeth sounds like the best thing that could happen to ya in that situation though..
 
UPDATE*** It's been a long time comin' but I'm finally able to gather my wits and bag 'em up.. Got this Runner run'n the way it's suppose to run tonight.. It turned out to be the upstream O2 sensor... It wasn't suppose to be a O2 sensor.. The upstream sensor is a Air/Fuel Ratio sensor.. I've read many of post where people were claimin' that they were the same thing.. I'm proof that they are NOT.. I have no idea how places that sell these types of parts don't say "I show a downstream O2 for your model but not a upstream"... WTF.. This was actually the second O2 I had put in the upstream but this time around I had replaced the whole exhaust from mani back which is probably why it gave me fits for 7 long months.. But I have to end with a big THANKS to all who threw out possible issues that 'could've' been.. I should be good for another 100 thou with all the new parts I've put on so it was no means a waste of time or $.. I couldn't of done shat without this forum.. Thanks guys & gals (maybe)..!!
 
Glad to hear your truck is running well again! :reddance: I read through this whole thread and towards the end, you had me biting my teeth as far as what was wrong with it!
 
Had you put in a universal type sensor where you solder the old plug onto the new sensor wires? Because the plugs on the O2 sensors and the A/F sensors are different so as to avoid this happening...

Congrats on figuring this out....at least you have a really well-maintained engine!
 
Mudtallica said:
I'll start with this... It's a 99 SR5, 3.4V6, auto... I'm having issues with the way it's running.. At idle, you can hear the motor revving up & down.. Put it in gear and it does the same thing when you give it gas.. Kinda like if you were pumping the gas pedal up & down a little bit but the RPM's do not fluctuate with the "sound" of the motor.. The check engine light is no longer on since I have changed out the following: Both O2's, both cat converters, muffler, plugs (Bosch), plug wires (NGK), all 3 coil packs (OEM), air filter (FRAM).. I took out the MAF sensor and cleaned it since it's only a yr old.. It's running better than it was but not perfect.. It didn't do what it's doing now before I changed all this... I can't remember the codes that it was giving me but I plugged up my scanner to check the I/M monitors and all was OK except the catalyst monitor and the EVAP monitor.. They were both "inconclusive".. Any ideas or thoughts out there would be greatly appreciated.. I do not want to take this to a dealership to have them "fix" this.. unless I HAVE TO..
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The clue was there in your first post and we all missed it! If there are two cats, you need a front A/F and a rear o2. Kicking myself....
 
TheDurk said:
Had you put in a universal type sensor where you solder the old plug onto the new sensor wires? Because the plugs on the O2 sensors and the A/F sensors are different so as to avoid this happening...

Congrats on figuring this out....at least you have a really well-maintained engine!
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Nope.. No universal type.. Get ready for this.. When I climbed under to change it out, I remember thinkin' "I guess this one (sensor) was made on a ****in' Friday 'cause the ridges are on the wrong side of the plug".. Cue the box knife for a little widdlin'.. After the ridges were gone, it plugs right in.. Always learnin' man... Always learnin'...
 
xcmountain80 said:
You could do a URD simulator like a few of us did and skip replacing your cat or the 02 sensor.
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I have thought about this several times.. Maybe down the road.. Right now, we're gettin' along pretty good (me & 4rnr) so out of respect, I shall not try to "trick" her right now..
 
It amazes me every-time somebody's engine is having a problem all of a sudden the Bosch plugs is the red herring

I have those same bosch 4 point plugs with +15000 km on them , zero issues, zero fouling, starts like a beast in -32deg C

yeah its my engine I decided to use them.....
 
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