3.4L Missfire on Cyl 1 & 2
09-14-2017, 06:27 AM
#21
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Any update to this thread?
i have a '00 worth 258k on it and noticed a few days ago it running rough after it had been driven and warmed up.
CEL came on a few days later with P0302 code.
Ive been reading posts and watching YouTube.
Plugs have about 60k on them
Coil packs are original as are injectors
If the 2 and 5 coil pack is the issue wouldn't both 2 and 5 be showing issues?
Should I just jump in and change the #2 injector and coil pack and wires to cover all bases?
Also i see about replacing the pre cat sensor? How hard is it to swap that?
the Yota isn't my main vehicle any more tho I do use it often to keep miles off my F150
I'm not diving it till I get the misfire resolved
what's best source for injectors?
Thx for the help
i have a '00 worth 258k on it and noticed a few days ago it running rough after it had been driven and warmed up.
CEL came on a few days later with P0302 code.
Ive been reading posts and watching YouTube.
Plugs have about 60k on them
Coil packs are original as are injectors
If the 2 and 5 coil pack is the issue wouldn't both 2 and 5 be showing issues?
Should I just jump in and change the #2 injector and coil pack and wires to cover all bases?
Also i see about replacing the pre cat sensor? How hard is it to swap that?
the Yota isn't my main vehicle any more tho I do use it often to keep miles off my F150
I'm not diving it till I get the misfire resolved
what's best source for injectors?
Thx for the help
09-14-2017, 07:23 AM
#22
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Start with the stuff that needs to be replaced--plugs and wires. Then check if the code goes away.
There's a way to check coil packs and injectors. Simple tests with a multimeter are one avenue. Resistance, voltage for instance.
Lot of checking first, as misfires can be caused by a variety of things. Check for spark, fuel, ignition, and electrical. May involve certain sensors.
Pre-cat sensor is easy. Depends on how bad things are rusted down there. Can be a challenge if the nut is rounded off. Misfire codes tend not to involve it, but it's a part that needs changing every now and then.
Injectors...best choice is OEM but can be $$. Remanufactured is a less expensive option. But check them first. They tend to be culprits, by everyone's story is different.
Winter, how did things go with your runner?
There's a way to check coil packs and injectors. Simple tests with a multimeter are one avenue. Resistance, voltage for instance.
Lot of checking first, as misfires can be caused by a variety of things. Check for spark, fuel, ignition, and electrical. May involve certain sensors.
Pre-cat sensor is easy. Depends on how bad things are rusted down there. Can be a challenge if the nut is rounded off. Misfire codes tend not to involve it, but it's a part that needs changing every now and then.
Injectors...best choice is OEM but can be $$. Remanufactured is a less expensive option. But check them first. They tend to be culprits, by everyone's story is different.
Winter, how did things go with your runner?
09-14-2017, 07:34 AM
#23
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Thx
I'll start with plugs, wires and 02 sensor and go from there
I'll check the coil packs and maybe swap locations of 2 when doing the plugs.
Im guessing I'll have to do the injector since with 258k it's probabaky not the easier fix
since that seems to be my luck haha
I'll start with plugs, wires and 02 sensor and go from there
I'll check the coil packs and maybe swap locations of 2 when doing the plugs.
Im guessing I'll have to do the injector since with 258k it's probabaky not the easier fix
since that seems to be my luck haha
10-02-2017, 06:24 AM
#24
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Any update?
When I did my injectors, the replacement batch had 2 that were DOA. So my problem improved, but didn't go away, until I replaced MORE injectors (or rather replaced them again).
I would still try to move injectors/coils/wires/etc. to see if you can get the error code to move. Are you down to just the one cylinder giving you trouble? When your CEL comes on, is it solid or does it blink?
When I did my injectors, the replacement batch had 2 that were DOA. So my problem improved, but didn't go away, until I replaced MORE injectors (or rather replaced them again).
I would still try to move injectors/coils/wires/etc. to see if you can get the error code to move. Are you down to just the one cylinder giving you trouble? When your CEL comes on, is it solid or does it blink?
10-02-2017, 01:50 PM
#25
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Yesterday I finally got around to working on the 4Runner
Changed plugs( Denso factory ones), wires (blue NGKs) and aftermarket coil packs. Also replaced the forward o2 sensor
Drove it to work today and errands at lunch. No more CEL or codes but on the drive home on the Hwy I was getting intermittent shuddering/detonation.
ill keep driving it and see if the intermittent shuddering gets worse or a code and CEL comes back
Maybe I got a bad coil pack. I still have the Denso factory ones with 257k miles on them I removed
Changed plugs( Denso factory ones), wires (blue NGKs) and aftermarket coil packs. Also replaced the forward o2 sensor
Drove it to work today and errands at lunch. No more CEL or codes but on the drive home on the Hwy I was getting intermittent shuddering/detonation.
ill keep driving it and see if the intermittent shuddering gets worse or a code and CEL comes back
Maybe I got a bad coil pack. I still have the Denso factory ones with 257k miles on them I removed
10-07-2017, 07:50 AM
#26
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I swapped out the new aftermarket coil packs for the Densos I removed.
Still issues when warmed up, intermittent misfires. I drove about 150 miles over the last 2 days with most of those miles with the 4Runner warmed up. It'll drive fine for awhile and out of nowhere it'll misfire for a few seconds and then go away.
No CEL at all since I changed the plugs, wires and packs about 200 miles ago. Very frustrating.
Am I doing any possible harm by driving it when it's misfiring?
I guess I'll eventually have to change the injectors but it's hard to know which one to change since no CEL. When this first start it said cyl #2. I'd hate to take the intake off to get to the injectors, replace one and still have the issue but it might be overkill and money wasted to change them all!
If I'm not risking any damage I may just continue to drive it till it gets worse or a CEL shows up.
Still issues when warmed up, intermittent misfires. I drove about 150 miles over the last 2 days with most of those miles with the 4Runner warmed up. It'll drive fine for awhile and out of nowhere it'll misfire for a few seconds and then go away.
No CEL at all since I changed the plugs, wires and packs about 200 miles ago. Very frustrating.
Am I doing any possible harm by driving it when it's misfiring?
I guess I'll eventually have to change the injectors but it's hard to know which one to change since no CEL. When this first start it said cyl #2. I'd hate to take the intake off to get to the injectors, replace one and still have the issue but it might be overkill and money wasted to change them all!
If I'm not risking any damage I may just continue to drive it till it gets worse or a CEL shows up.
10-07-2017, 10:53 PM
#27
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See if you can hook up a scan tool that can tell if there's any pending codes. As far as the troubleshooting, may be time to look at testing the injectors. Try switching one from the good cylinders onto the #2.
10-10-2017, 04:04 PM
#28
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Finally got CEL today.
P300 and P302.
So still showing the #2 cyl having the misfire.
I guess replacing that injector will be my next task.
From what I've seen getting to the injector the intake both top and bottom has to come off and replacing a gasket or 2 for the intake makes sense while at it.
P300 and P302.
So still showing the #2 cyl having the misfire.
I guess replacing that injector will be my next task.
From what I've seen getting to the injector the intake both top and bottom has to come off and replacing a gasket or 2 for the intake makes sense while at it.
10-10-2017, 07:07 PM
#29
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Just so you know, P0300 means you should also check the other 5 cylinders. One or more of them also are misfiring.
Last edited by 75w90mantraN; 10-10-2017 at 09:29 PM.
10-16-2017, 01:05 PM
#31
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https://www.yotatech.com/forums/f2/p...-p0303-295724/
10-18-2017, 09:38 AM
#32
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I'm coming in late to this thread but I too had a similar issue. I chased everything down and in the end I replaced all my injectors with a very low cost option in ebay and it's been perfect ever since. Here's my thread.
https://www.yotatech.com/forums/f2/p...-p0303-295724/
https://www.yotatech.com/forums/f2/p...-p0303-295724/
I was going to ask what is the best choice for new injectors if going to replace them all.
I assume yours were re manufactured ones?
Did you do anything to text them before putting everything back together?
I'll probably start on this this weekend as the 4Runner isn't my daily driver any more but when running well I have been using it 3-4x/week to commute to work.
11-07-2017, 05:42 AM
#33
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Update
I got a new set of factory injectors off eBay for about $125. I followed the step by step how to online another owner made.
Took my time and labeled everything I took apart.
Got everything back together and the front pass side injector seal didn't seat properly and it was spraying fuel!! Had to take most apart again to reseat it.
In doing that I dropped one of the fuel line washers down near the timing belt cover and while trying to retrieve I pushed it further away and couldn't get it!
Luckily found one that worked from the local auto store.
Also while trying to retrieve the dropped washer I broke the coolant overflow spout on the radiator! I was able to get the hose back on somewhat and it drips a little after it warms up. I may eventually have to find a better fix.
I've put about 225 miles on it since the new injectors and no misfire issues, no CEL. Throttle response seems better too.
If you are hesitant to tackle this job it's really not that bad if you follow the HowTo online.
I got a new set of factory injectors off eBay for about $125. I followed the step by step how to online another owner made.
Took my time and labeled everything I took apart.
Got everything back together and the front pass side injector seal didn't seat properly and it was spraying fuel!! Had to take most apart again to reseat it.
In doing that I dropped one of the fuel line washers down near the timing belt cover and while trying to retrieve I pushed it further away and couldn't get it!
Luckily found one that worked from the local auto store.
Also while trying to retrieve the dropped washer I broke the coolant overflow spout on the radiator! I was able to get the hose back on somewhat and it drips a little after it warms up. I may eventually have to find a better fix.
I've put about 225 miles on it since the new injectors and no misfire issues, no CEL. Throttle response seems better too.
If you are hesitant to tackle this job it's really not that bad if you follow the HowTo online.
