2007 V8 acceleration stumble?

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05CTSV

New member
I've searched and haven't found quite what I'm experiencing.

When in drive(4th its better) if I stab it every now and then it falls flat on its face. Happened so bad yesterday that the radio even cut out for that one second before it picked up.

I typically ride in 4th gear because its better but not 100%.

It's not hesitation by drive by wire. It's a mis or stumble. No codes thrown.

I've got 84k on the truck and am going to change the air filter, plugs and check the cleanliness of the MAF. Also, will do a ecu relearn with battery.

Anything else I should look into? Please don't beat me up on search this or that, just looking for a couple helpful opinions/pointers.
 
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I am no expert but I'm pretty sure I could toss the battery out the window while driving without the car noticing?

Alternator is the voltage producer and regulator when running.
 
05CTSV said:
I am no expert but I'm pretty sure I could toss the battery out the window while driving without the car noticing?

Alternator is the voltage producer and regulator when running.
Click to expand...

A catostrophic battery failure can do this, but it happens very rarely. As stated, alternator more likely. A bad throttle position sensor or clogged injectors could do that too.
 
Truck starts perfect. Battery out. Alternator is 90% out. Car runs perfect. .

Only stumbles on a rapid pedal stab almost a wot stab. It bogs then goes.

Can't believe nobody can relate. Lol 1000 threads on shocks. None on engine stumbles :)
 
When was timing belt last changed? Some have suggested a stretched timing belt could act funny with VVTI.
 
I've got 84k on the truck. Timing belt is original.

Normal driving and startup is ideal. Sudden acceleration it falls on its face for a second.
 
I have had the same thing happen to me when driving through deep snow. I hit the gas hard and the motor did nothing for a second then i almost got stock.
 
Raging Canuck, that sounds like VSC kicking in. Wonder if the same is happening to 05CTSV for some reason? When you floor it, does the indicator for VSC light up? Any beeping?
Just for HA HAs, try performing a zero point calibration. Can't hurt.

Also try this: on a STRAIGHT section of road, lock the center diff. and try it. See if it still falls flat.
Just don't turn on dry roads with it locked.
 
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05CTSV said:
Truck starts perfect. Battery out. Alternator is 90% out. Car runs perfect. .

Only stumbles on a rapid pedal stab almost a wot stab. It bogs then goes.

Can't believe nobody can relate. Lol 1000 threads on shocks. None on engine stumbles :)
Click to expand...

How have you verified that the 12v Battery is good and that the Alternator is providing enough current?

An issue like this seems unlikely to affect a system like the radio if it were fuel or ignition related; what exactly do you mean by "radio cut out?" It could be a result of poor throttle learning depending on when/if the battery was drained/jump started/replaced recently. Another possibility is a dirty MAF and/or throttle plate, if you're going to clean the Throttle Body it is imperative that you do so with the ignition OFF as forcing the blade open with the key on can damage the system. After cleaning the throttle body I'd recommend disconnecting the battery 5-10min and relearning the idle properly for best results.

It is possible that there's a "dead spot" in either the throttle body and/or accelerator pedal; but for it not to set a DTC seems unlikely as they have offset rheostats specifically to detect for those types of issue (though if it is a small enough dead spot it could not trip a DTC I suppose?)
 
I am almost sure its not the battery. We all know the battery is out of the equation when engine is running. Regardless of alternator charge voltage. If it was an alternator charge issue then it would have shown the signs of alternator issues.

This is a misfire clearly.
 
05CTSV said:
I've got 84k on the truck and am going to change the air filter, plugs and check the cleanliness of the MAF. Also, will do a ecu relearn with battery.
Click to expand...

Do this, plus some clean 93 octane and maybe a fuel injector cleaner bottle and report back.
 
05CTSV said:
I am almost sure its not the battery. We all know the battery is out of the equation when engine is running. Regardless of alternator charge voltage. If it was an alternator charge issue then it would have shown the signs of alternator issues.

This is a misfire clearly.
Click to expand...

That's not entirely true on a modern CAN vehicle. The battery still has the critical function of absorbing and smoothing out the voltage variation in an alternator's charging current. Not to mention modern alternators are NOT designed to run the vehicle, nor charge up a dead battery; they are designed to "top-off" a good battery and maintain a constant voltage. Smooth, constant, power is critical for ECM reference voltages and sensor inputs; LOTS of issues can occur due to a dead battery and over-worked alternator on modern OBDII CAN vehicles.

That's why I was asking how you verified that the alternator and the battery were good. I would have a auto-parts store test the battery and alternator if they have a hand-held tester (they should) as it will load the battery up and verify it is functioning correctly.
 
OK understood. I've never experienced any issues with it and I wish I didn't mention the radio.

If you the truck is in drive and I had to stomp on it for whatever reason. The kickdown into another gear and the engine both stumble before doing it.

It is better in fourth or third. But still noticeable.

The truck near stalled the other day when the radio quickly cut in and out which I think was related to engine RPM and stall conditions and not the other way around (ecu or voltage lost, then resulting in stall condition)
 
05CTSV said:
OK understood. I've never experienced any issues with it and I wish I didn't mention the radio.

If you the truck is in drive and I had to stomp on it for whatever reason. The kickdown into another gear and the engine both stumble before doing it.

It is better in fourth or third. But still noticeable.

The truck near stalled the other day when the radio quickly cut in and out which I think was related to engine RPM and stall conditions and not the other way around (ecu or voltage lost, then resulting in stall condition)
Click to expand...
All of this points to a misfire or performance issue, just wondered if anyone experiencing anything similar ever?
 
The radio could be a red herring. But most every modern Toyota I have seen stall usually doesn't affect the auxiliary circuits because they have constant power as long as the ignition is in the "on" position. For that circuit to power off/on by itself indicates a power supply issue somewhere.

We need to determine if the issue is logical, fuel, ignition, and/or electrical before we can really do much of anything. Did you try cleaning the MAF, Throttle Body, relearning the idle? Do you have access to an OBDII scanner that can read/display Datalist information?
 
05CTSV said:
I've searched and haven't found quite what I'm experiencing.

When in drive(4th its better) if I stab it every now and then it falls flat on its face. Happened so bad yesterday that the radio even cut out for that one second before it picked up.

I typically ride in 4th gear because its better but not 100%.

It's not hesitation by drive by wire. It's a mis or stumble. No codes thrown.

I've got 84k on the truck and am going to change the air filter, plugs and check the cleanliness of the MAF. Also, will do a ecu relearn with battery.

Anything else I should look into? Please don't beat me up on search this or that, just looking for a couple helpful opinions/pointers.
Click to expand...

Mine does it as well, never been able to cure it or figure out what exactly is causing it.

With mine it bogs down/misses if you press the pedal down about 65-75%. 25% and you get a nice downshift one gear, 100% and it goes like hell, but there is that magic area where it just goes flat and seems confused.

I did everything Blacksworksinc suggested above plus new plugs, timing belt, etc. and had zero luck.
 
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