Good to know, I may just replace the O2 then see if that helps, if not gonna do the coil pack swap out to see if that's the issue on mine.
Please help! bucking at highway speeds
- Thread starter Dagobah
- Start date
Good to know, I may just replace the O2 then see if that helps, if not gonna do the coil pack swap out to see if that's the issue on mine.
Squirt
New member
I did the coil pack swap the other day and nothing changed. tomorrow if I have time I'm going to pick up some new plug wires..not sure if that's the issue, but the ones on mine look like the originals so it's worth a shot.
Well, my plugs and wires were done only 10k ago so that may not be it for me. Hopefully it fixes your issue and I'm hoping the O2 sensor is mine but we'll see. I'm about due for a timing belt so I'm going to change every sensor I can reach when I'm in there just for good measure.
gamefreakgc
Elite Member
There's still two O2 sensors on all rigs. The different between the California and Federal (everyone else) is that the California had a different part number and sensor, your front one is actually a air/fuel ratio sensor and not just a basic O2 sensor. I think the rear is a different part number as well due to the position of the second cat (California has two, Federal has one) and needing a longer wire harness.
Squirt
New member
sorry man, my bad..like you I was considering only one of them an actual o2 sensor.
replacing the plug wires fixed it temporarily. It's back now. The car seems to do fine if i stay within the first 1/3 of the pedal travel, and will wrap out to redline without hesitation. beyond 1/3 pedal and it sputters pretty bad. Sometimes i will get a backfire out of the intake. The coilpack resistance tested within spec. still no CEL so i'm not quite sure where i should start replacing parts. any ideas?
I thought I'd give some feedback and solution to my issue, which was exactly as described in this thread. Our '99 4Runner (V6, 3.4, automatic, 4x4) would start and idle just fine, but when travelling at highway speed it would occasionally buck, especially noticeable when pulling a trailer. It seems to get worse with time. No CEL. Also, hard acceleration was choppy, and not smooth. I did 3 things, the first of which I'm 99% sure fixed the issue: 1. Cleaned MAF sensor with alcohol and soft cloth, 2. Replaced spark plugs, 3. Replaced fuel filter. My 4Runner was due for new spark plugs and fuel filter, so I don't feel bad for replacing these at all. I'm 99% sure it was the MAF because there was an oily dust build up on the sensor. Now...I have a new problem. My 4Runner idles high (~1.2k), probably from me cleaning the throttle body. However, this is something I can deal with...I'm happy that it doesn't lunch/buck anymore.
Negra
New member
Im going to shoot a video today. Mine is hesitating, too, but not under load. Its the opposite, when Im just cruising at little to no throttle. I get this little stutter every so often. Still trying to diagnose... Everything is perfect about the rig, except this. Its not even that bad, I just like everything tight.
thegipper
New member
This is totally a shot in the dark but it may be your problem.
Sometimes the flexible gauge cluster circuit board can develop cracks on the wire pathways (not sure what to call it) and make your transmission not shift or shift erratically. I was having transmission issues (wouldn't shift out of 1st until it warmed up) and this was one of things that was suggested. It didn't fix my issue (mine is something mechanical in the tranny) but it *may be your problem.
The reason why it may be your problem is the people with the shifting problems also reported it acting up when they would turn on their brights and other stuff. And the "R" would be faintly lit up on the cluster even though they weren't in reverse. Not everyone had the symptoms and sometimes the symptoms were intermittent.
Let me see if I can find it in my post and I'll link it on here.
http://www.toyota-4runner.org/3rd-g...ng-when-cold-yes-i-know-its-normal-but-2.html
Post# 29, like I said its a long shot but worth checking out at least.
Sometimes the flexible gauge cluster circuit board can develop cracks on the wire pathways (not sure what to call it) and make your transmission not shift or shift erratically. I was having transmission issues (wouldn't shift out of 1st until it warmed up) and this was one of things that was suggested. It didn't fix my issue (mine is something mechanical in the tranny) but it *may be your problem.
The reason why it may be your problem is the people with the shifting problems also reported it acting up when they would turn on their brights and other stuff. And the "R" would be faintly lit up on the cluster even though they weren't in reverse. Not everyone had the symptoms and sometimes the symptoms were intermittent.
Let me see if I can find it in my post and I'll link it on here.
http://www.toyota-4runner.org/3rd-g...ng-when-cold-yes-i-know-its-normal-but-2.html
Post# 29, like I said its a long shot but worth checking out at least.
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Jason B
Official Vendor
Dude, thanks for the reply! I thought it might be my led tails, or the led hitch light I have that was going something weird with the voltage. I was going to unplug everything and see if it went away. I'll read your post now.....
Video of issue:
http://www.youtube.com/watch?v=40fAGOfDr38
EDIT!!!!
It was the 3rd brake light! This bulb being burnt out made my truck shift erratically (triggers torque converter lockup) when puttin the turn signals on in the final drive gear at highway speeds. If this bulb burns out, beware of this.
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drei4runner29
New member
I was having the same issues like the ones mentioned in this post. I noticed on mine that when mine would start bucking, I would lose some speed and when trying to accelerate their would be this loud whining noise whenever the RPMs would hit between 3000-4000. Took it in to my mechanic and he replaced the MAF sensor yesterday and took it out for a test drive and the bucking has stopped (cross your fingers that it stays stopped) after reaching around 70+ mph.
Now the only problem left is that I am losing too much power when going uphill. Prior to my bucking problem, I was able to go to certain uphills w/ no problem and keep my speed constant at a steady 70 mph at around 2500 rpms. Now after the bucking started I'm constantly losing power going up certain inclines where I had no problems before. Even at a constant 2500 rpms going up certain inclines where my 4runner could go up at a steady 70 mph, now I'm starting to go up to 60 mph or less. I am forced to use my overdrive to compensate and now when I use it, I am hearing a whining noise whenever the rpms go up to 3000+ rpms. I've taken it to my mechanic today and he did say he noticed it but doesn't know what it could be. He suggested it might be my exhaust system and my muffler could have gone bad and to take it to a muffler shop to just make sure.
Did this happen to anyone and what the fix could be? I don't want to have to keep taking it to the shop to figure out what could be wrong. I've changed the spark plugs and wires to OEM Denso products since I just had my 30k tune up, I've changed the MAF sensor yesterday, the O2 and air fuel ratio sensors have also been changed along w/ the catalytic converters last year to pass the smog.
Any help would be greatly appreciated. Thanks.
Now the only problem left is that I am losing too much power when going uphill. Prior to my bucking problem, I was able to go to certain uphills w/ no problem and keep my speed constant at a steady 70 mph at around 2500 rpms. Now after the bucking started I'm constantly losing power going up certain inclines where I had no problems before. Even at a constant 2500 rpms going up certain inclines where my 4runner could go up at a steady 70 mph, now I'm starting to go up to 60 mph or less. I am forced to use my overdrive to compensate and now when I use it, I am hearing a whining noise whenever the rpms go up to 3000+ rpms. I've taken it to my mechanic today and he did say he noticed it but doesn't know what it could be. He suggested it might be my exhaust system and my muffler could have gone bad and to take it to a muffler shop to just make sure.
Did this happen to anyone and what the fix could be? I don't want to have to keep taking it to the shop to figure out what could be wrong. I've changed the spark plugs and wires to OEM Denso products since I just had my 30k tune up, I've changed the MAF sensor yesterday, the O2 and air fuel ratio sensors have also been changed along w/ the catalytic converters last year to pass the smog.
Any help would be greatly appreciated. Thanks.
