Engine Stutters

T

tbryanh

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Engine Stutters

This is happening on both of my 3rd gen v6 4runners after they warm up.

Could this be a symptom of a dirty throttle body? A dirty MAF?

Both cars run good. One was tuned up recently (spark plugs, spark cables, and air filter), and I am going to tune the other one up soon.

Happens maybe 2 or 3 times on the way to work (25 miles), and on the way home.

Seems engine cuts out and back in quickly causing a mild jerk. Thanks.
 
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Is the dash CEL lit - read it if so - even if not - read it anyway - there maybe a Pending code for a clue.

I have not seen a dirty MAF or intake cause that symptom - they are more of a steady decline in performance and idling being super low.
 
I had similar symptoms. In "D" at low rpm and low speed, vehicle was in top gear and would suddenly feel like the paved town road suddenly turned to washboard for a second or two.
Driving in one gear lower (in "S") prevents this shudder effect. Try it as experiment.
Extensive investigation revealed a torque converter flex lock up failure. So it was not engine but tranny as the flex lock solenoid and valve are in tranny valve body.
An old Toyota problem across many years and models. Lots of info on internet, look up shudder, stutter, judder. Some technical bulletins written by Toyota over the years.
 
I drove on the freeway with overdrive off and still got the jerks. They seem to have less of an impact than when I put the overdrive on. The engine spins faster when overdive is off, so maybe there is more momentum within the engine with overdive off causing the impact to be less.


Not sure how helpful this test is. Will read for pending CEL codes on Thursday or Friday. Busy with my job right now. Thanks.
 
How old are your coils? Non Denso coils are junk on these. If your OEM ones are old then try putting new boots on them. Clean your IAC otherwise.
 
If it is in the torque converter lock-up system, down shifting usually changes the lock-up parameters. My issues were for 5th gen 750 tranny ,so will be different for another model tranny.
I my words , What was occuring is the flex-lock failed to release the locked torque converter lock up plates so the result was momentary brake affect. Kinda like a manual tranny in too high a gear for road speed. You need to slip the clutch.

I noticed it at 25-35 mph at about 1200-1500 rpm in top gear. Shifting to neutral seemed to cancel the shudder-but its shudder started and ended so fast I could not shift into neutral quick enough to be certain.
 
T4R2014 said:
How old are your coils? Non Denso coils are junk on these. If your OEM ones are old then try putting new boots on them. Clean your IAC otherwise.
Click to expand...

"How old are your coils?"
I don't know. One 4Runner had 130K miles on it when I bought it. It has 180K on it now. (Its the one that jerks the hardest.) The other 4Runner had 280K on it when I bought it. It has 360K on it now.

"Non Denso coils are junk on these."
How do you check the brand on the coil?

"If your OEM ones are old then try putting new boots on them."
Dealer doesn't sell boots, but i can get them through O'Reilly. (O'Reilly quit selling spark cables, but they still have boots, at least for now.)


"Clean your IAC otherwise."
Idle Air Control. That the little butterfly valve in the throttle body, right? That is used for cold start and to prevent high vacuum during deceleration, right?

Here is a thread on the IAH: IAC Valve Testing and Cleaning

Maybe expand on how that might relate to the problem. Thanks.
 
Hungryhawk said:
If it is in the torque converter lock-up system, down shifting usually changes the lock-up parameters. My issues were for 5th gen 750 tranny ,so will be different for another model tranny.
I my words , What was occuring is the flex-lock failed to release the locked torque converter lock up plates so the result was momentary brake affect. Kinda like a manual tranny in too high a gear for road speed. You need to slip the clutch.

I noticed it at 25-35 mph at about 1200-1500 rpm in top gear. Shifting to neutral seemed to cancel the shudder-but its shudder started and ended so fast I could not shift into neutral quick enough to be certain.
Click to expand...

Hmmm...
 
T4R2014 said:
Nothing lasts forever. They will pass the FSM resistance test but they still lose performance with time. You can get NGK boots on Amazon.
Click to expand...

Good price too! I'll order some.

3 pc NGK Ignition Coil Boots compatible with Toyota 4Runner 3.4L V6 1996-2002
Visit the Sixity Auto Store
$30.31
 
I bet these are good too?

3 pc DENSO Direct Ignition Coils compatible with Toyota 4Runner 3.4L V6 1996-2002


3 pc NGK Ignition Coils compatible with Toyota 4Runner 3.4L V6 1996-2002
 
No telling where the NGK coils are made, nor are they OE on these engines. Get the Denso, should be a nice power bump from old coils.
 
T4R2014 said:
No telling where the NGK coils are made, nor are they OE on these engines. Get the Denso, should be a nice power bump from old coils.
Click to expand...

The only Denso on Amazon are out of my shipping area. eBay doesn't have them. The dealer wants over double of Amazon's price.

Where can I get Denso besides the dealer?
 
tbryanh said:
The only Denso on Amazon are out of my shipping area. eBay doesn't have them. The dealer wants over double of Amazon's price.

Where can I get Denso besides the dealer?
Click to expand...

I think I actually got my last set from WalMart. Hopefully they deliver to you.
 
Walmart is out of stock. RockAuto has an incredibly good price but says "Non-stock item--shipping delayed up to 2 business days"

RockAuto looks incredibly good. I never shopped there. Are they reputable?

I saw RockAuto listed an Ignition Control Module, ICM. Maybe this is causing my problem?
 
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