2007 V8 acceleration stumble?
- Thread starter 05CTSV
- Start date
BlackWorksInc
New member
Okay, we need to clarify something here.
Are you guys talking about the "lag" in acceleration when you go heavy into the pedal and/or WOT (Wide Open Throttle) where the vehicle seems to take a moment before shifting and then picking up speed (almost like it's taking a deep breath before taking off).
OR
Are you talking about the engine actually misfire, losing RPMS, and almost stalling out as you accelerate?
Those are two completely different issues, one is a weird quirk on how it accelerates; the other implies there's an issue and the engine is not running correctly. I have had customers in the past confuse the two only to spend a lot of time verifying that the vehicle is not misfiring, bogging down, or stalling.
Misfiring would imply that the engine is failing to fire the cylinders correctly and could be anything from back-firing, dead hole, a noticeable shake as the engine isn't running correctly.
Bogging Down/Stalling implies that the vehicle cannot maintain RPMs and the engine is in danger of actually shutting off if it gets worse, the engine will stumble, shake, and outright stop running.
If it's just lagging/pause between shifting you'll notice it will drop RPMs maybe without any adverse effects in operation and the transmission doesn't seem to grab the gear quickly.
Are you guys talking about the "lag" in acceleration when you go heavy into the pedal and/or WOT (Wide Open Throttle) where the vehicle seems to take a moment before shifting and then picking up speed (almost like it's taking a deep breath before taking off).
OR
Are you talking about the engine actually misfire, losing RPMS, and almost stalling out as you accelerate?
Those are two completely different issues, one is a weird quirk on how it accelerates; the other implies there's an issue and the engine is not running correctly. I have had customers in the past confuse the two only to spend a lot of time verifying that the vehicle is not misfiring, bogging down, or stalling.
Misfiring would imply that the engine is failing to fire the cylinders correctly and could be anything from back-firing, dead hole, a noticeable shake as the engine isn't running correctly.
Bogging Down/Stalling implies that the vehicle cannot maintain RPMs and the engine is in danger of actually shutting off if it gets worse, the engine will stumble, shake, and outright stop running.
If it's just lagging/pause between shifting you'll notice it will drop RPMs maybe without any adverse effects in operation and the transmission doesn't seem to grab the gear quickly.
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Both. Ha-ha. The lag I've always noticed but it has gotten worse and my main.point of this thread was.
Is there anything on this engine I should look at besides what I've listed as normal tune up items?
So engines are known for certain things and I was just checking with the community. Seems not to be anything about this engine besides exhaust manifold cracking.
I think I might have popped the hood last year on this thing ha-ha. This is my A to B vehicle for dogs and it doesn't get too much attention but I still take Care of my things. I really don't know anything about the Toyota engine lineup. Not much anyways. So far it's treated me wrll
Is there anything on this engine I should look at besides what I've listed as normal tune up items?
So engines are known for certain things and I was just checking with the community. Seems not to be anything about this engine besides exhaust manifold cracking.
I think I might have popped the hood last year on this thing ha-ha. This is my A to B vehicle for dogs and it doesn't get too much attention but I still take Care of my things. I really don't know anything about the Toyota engine lineup. Not much anyways. So far it's treated me wrll
BlackWorksInc
New member
Well how many miles are on the vehicle?
If you're around 90~110k I'd recommend the following items be addressed if they haven't as normal maintenance items that could improve engine performance as a result.
-Replace Spark Plugs (Iridium)
-Clean MAF/Throttle Body & Relearn Idle
-Check/Replace Engine Air Filter
-Run some Seafoam/Injector cleaner for a tank of gas or two (it probably won't clean the injectors completely but it usually helps improve the spray pattern a little bit, I like Seafoam myself)
-Timing Belt (Should really consider doing it if your in the 90~110k range if it hasn't been done in the last 9yr/90k)
-Transmission fluid service (100k is a good number to do a drain and fill or complete flush on the WS ATF transmissions.)
That should help improve the engine performance so it's not misfiring/bogging down a bit. The lag will always be there on heavy acceleration, it's a bit weird but it's like Toyota programmed the 4Runner to take a big deep breath before sprinting off the line; kind of funny when you think about it that way, mine does the same thing sometimes.
Post Note-
Also keep in mind if you disconnect the battery for 5~10minutes to relearn the idle you're also going to need to relearn the long term memory. So drive the vehicle as you normally would and don't be too aggressive if you aren't normally as it will take 20~50miles.
If you're around 90~110k I'd recommend the following items be addressed if they haven't as normal maintenance items that could improve engine performance as a result.
-Replace Spark Plugs (Iridium)
-Clean MAF/Throttle Body & Relearn Idle
-Check/Replace Engine Air Filter
-Run some Seafoam/Injector cleaner for a tank of gas or two (it probably won't clean the injectors completely but it usually helps improve the spray pattern a little bit, I like Seafoam myself)
-Timing Belt (Should really consider doing it if your in the 90~110k range if it hasn't been done in the last 9yr/90k)
-Transmission fluid service (100k is a good number to do a drain and fill or complete flush on the WS ATF transmissions.)
That should help improve the engine performance so it's not misfiring/bogging down a bit. The lag will always be there on heavy acceleration, it's a bit weird but it's like Toyota programmed the 4Runner to take a big deep breath before sprinting off the line; kind of funny when you think about it that way, mine does the same thing sometimes.
Post Note-
Also keep in mind if you disconnect the battery for 5~10minutes to relearn the idle you're also going to need to relearn the long term memory. So drive the vehicle as you normally would and don't be too aggressive if you aren't normally as it will take 20~50miles.
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Blackworksinc, going to respond to both of your posts here in this one.
It is hard to describe, it isn't a lag like a normal auto when it downshifts a couple gears. The difference being the RPMs either stay stagnant or go to idle instead of increasing while waiting for the new gear.
It is really odd, and it makes you get off the throttle because it is so weird. As i mentioned mine doesn't do it at WOT but around 75% like i just confused the hell out of the computer.
I have done everything on your list with the exception of trans fluid change, but it is on my list to do soon.
I have a 2006 w/ 118,000.00 miles.
I have also had what seems like it drops the RPMs and then grabs the gear it was in again instead of another one...which is great when passing. If I stay in the throttle it will take another shot at it and get the intended gear normally.
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I would add clean IAC to the list, otherwise an awesome list
Yes more for idle than performance, but might as well once you are cleaning MAF/TB.
BlackWorksInc
New member
I would add clean IAC to the list, otherwise an awesome list
Yes more for idle than performance, but might as well once you are cleaning MAF/TB.
4th Gens and all Toyotas (hell almost all manufacturers) that use a "Throttle by Wire" set-up do not have an IAC. This is why throttle position/idle relearn is so critical if the battery has been run low/disconnected too long.
The modern Throttle by Wire systems actually manipulate the throttle blade via ECM input to allow for idle bypass, eliminating the need for a separate passage and IAC. In fact, the throttle functions independent of the customer's input sometimes, idle being one example, and shifting between gears being another (in some cases the ECM may actually close the throttle depending on what it thinks it should do to "smooth" out shifts; this happens fast enough that engine performance isn't hurt and is mostly unnoticed by the customer besides a smoother feeling transition of gears.)
It's either fuel, air or spark.
It's probably not "air" since most of the time it runs.
Could it be "fuel"? A long time ago I had a car stumble when punching it and it turned out to be a clogged fuel filter. The float bowl in the carb would empty faster than the pump could refill it.
How about "spark"? This seems more likely. If you're saying the radio is going out, that points to an electrical problem. I'd check all the major connections between battery, starter and alternator. Maybe a bad ground wire somewhere? When you gun it, the engine rotates on its mounts briefly. Maybe this is tugging/exposing a bad connection somewhere.
Just my $0.02.
It's probably not "air" since most of the time it runs.
Could it be "fuel"? A long time ago I had a car stumble when punching it and it turned out to be a clogged fuel filter. The float bowl in the carb would empty faster than the pump could refill it.
How about "spark"? This seems more likely. If you're saying the radio is going out, that points to an electrical problem. I'd check all the major connections between battery, starter and alternator. Maybe a bad ground wire somewhere? When you gun it, the engine rotates on its mounts briefly. Maybe this is tugging/exposing a bad connection somewhere.
Just my $0.02.
luke87gt
New member
You are really throwing us for a loop with the radio cutting out detail.
Are you sure the radio cut out or did your brain cut out during the shock and disappointment of the acceleration stumble
Totally kidding, but I'm serious about addressing why the radio cut out because even if the car stumbled or died, it should't kill the radio unless there is some electrical issue... I think.
Are you sure the radio cut out or did your brain cut out during the shock and disappointment of the acceleration stumble
Totally kidding, but I'm serious about addressing why the radio cut out because even if the car stumbled or died, it should't kill the radio unless there is some electrical issue... I think.
Maybe forget the radio. It did it. First time its ever done it but also it died for a millisecond. I know this cuz I had it up loud when turning and someone was merging into me at fifty. I went from drive (5th,6th?) To third or second and it fell on its face for a second and it went silent. Then it picked back up. Downshifted and I was fine. My wife even commented with. That was weird?
I have all of the above items ready to go minus trans flush...thought these never needed a flush
I have all of the above items ready to go minus trans flush...thought these never needed a flush
I think you guys may have an actual problem...but I was wondering if there was any experience with the drive by wire programmers ? https://www.sprintboostersales.com/...end=2009&make=Toyota&model=4Runner&engine=Gas
Sprint booster $300 bucks !
Or if anyone knows any tricks to take the "smoothing" out of the 1st to 2nd gear shift...I hate that mild slip feeling
Sprint booster $300 bucks !
Or if anyone knows any tricks to take the "smoothing" out of the 1st to 2nd gear shift...I hate that mild slip feeling
bamma
New member
BOFFROAD
New member
No expert here and I haven't read every reply in this thread, but you should hook it up to an OBD reader even though the check engine light isn't present. There can be a code present however the computer may not be activating the light because it doesn't think it's important enough.
