Slight Hesitation during Accleration... no Codes... Help please

[Chinee]

Posted this in the Technical Forum as well.

2002 Sequoia, 250K miles

Been having rough acceleration for the last month or so, and I cannot find the problem. No codes, so that makes it harder. It happens intermittently and mostly when:
- Using Cruise Control, you can feel the slight misses (light sputtering), not enough to create a jerky action, but it is there every 5-10 seconds
- Accelerating from a slow down while turning, e.g. turning right through a Yield sign, sometimes there's enough hesitation for there to be a jerk
- Accelerating very slowly from 20 to 50 mph, you can feel the light sputtering and occasionally there'll be a small jerk

What I've done:
- Changed plugs in Feb 2012, just 17K miles ago, NGK Iridiums, pulled plugs last night and inspected, gaps were at .031, no carbon buildup or otherwise
- Cleaned intake with carb cleaner
- Changed fuel filter
- Ran a tank with Seafoam
- Changed air filter
- I also changed the TPS a few months ago after getting the appropriate code, maybe I messed up on the install?

Thinking:
- ignition coils
- TPS
- the other TPS (forgot the name, APPS?, on the other side of the intake)
- changing the plugs
- adding a water remover to gas tank

But remember no codes, which would indicate problems with the TPS and ignition coils.

Any ideas anyone?

[henway2]

When you say "no codes", what does that mean?

[Chinee]

... from the OBD Scan Tool, no Check Engine Light.

[tundra3400]

did you clean the MAF? and if so did you use MAF cleaner?

[henway2]

This has been described by many Sequoia owners, including myself. So far, no one has found the cause. The cause of this hesitation is very difficult to track down, because so many factors are involved, like you mention.


Sequoia Bogging Down

I wish you luck in finding the cause of this problem, it has been bothering me for 4 years now.


2002 Toyota Sequoia SR5 4WD 108,000 mi.

[Chinee]

did you clean the MAF? and if so did you use MAF cleaner?

Can you suggest a cleaner before I go out there trolling the auto parts store?

[tundra3400]

any MAF cleaner they have works as long as it says safe to use on MAF sensors. just take out the sensor( 2 small screws) and unplug it. let it try completely for a few mins and reinstall it.

[Chinee]

Cleaned the MAF, first time in 250K miles... no change. Will probably head to the dealer next week, but thinking about changing plugs today to so if it might me a bad plug that's firing intermittently.

Has anyone gone to the dealer to investigate this issue?

[spinn]

I don't have the same problem, as my decrease in acceleration only seems to occur at around 70-75mph, whether out/in cruise-control mode, and it's intermittent. I've only seen it once mentioned that it could be the catalytic converters getting clogged up at full throttle. Not saying that's your problem, but with that many miles (I have +200K), maybe your cats could be getting bad.

[Chinee]

Update... After 1,400 miles and 32 days, I am cautiously optmistic that it's fixed. I was researching cat converters to see what the specific symptoms of failing cats would be... didn't match up to my problems. Saw a FB post about a GS400 having hesitation and stuttering between 1100 and 2200 rpm... very much like my Seq, but the specific problem and solution were not listed. It mentioned the GS having a 1UZFE engine, which has a similar lettering code to our 2UZFE engine (still have no idea if the engines are similar), and that caused me to go cruising the Lexus forums. Found someone with an ES with similar problems, (but it has a V6, not a V8 like the Seq's) and it turned out to be EGR and idle control issues; decided to check my PCV. I pulled it and it rattled, so it should be good, decided to blast some Carb Cleaner through both ends and shake it up some. Re-installed and after a 9 mile test drive the hesitation and stuttering seem to be gone.

I am still not 100% sure it's fixed, since it's nighttime and the temps are lower, 60's, so it performs differently from during the daytime, but I will be checking it out during my errand runs tomorrow. I will be back with another post tomorrow.

[Chinee]

My optimism just went out the window... Damn!

[tundra3400]

you might want to have the idle speed control motor cleaned. my v6 tundra has one and it would do the same things you are describing. in not exactly sure where it is but its on the intake/TB somewhere.

[Chinee]

The V6 Tundras have an Idle Air Control Valve, the V8s have a Throttle Control Motor, attached to theTPS, Throttle Position Sensor. Researching these now.

[Chinee]

Update... cleaning the PCV valve did result in an improvement; the hesitation was less often and softer, so I replaced the PCV on Friday. Also changed the plugs, took out the 10-month old NGK Iridiums with ~18K miles and replaced them with the common NGK plugs, about $2.30 each. I was almost ready to say the symptoms were gone. But today I was going at a steady cruise, just under 50mph, rpms in between 1500 and 2K, accelerated slightly, and I felt hesitation. Very soft and almost imperceptible, but it was there, about 3 stutters. Tried to reproduce it for the next 3-4 miles but could not.

At this point, I am returning the Seq to the wife and let her tool around in it for a spell to see if the hesitation returns with her; I suspect it will. Getting a little frustrated, even looked up the kbb price, about $4,000. I will likely monitor the performance over the next few weeks and see what happens... fingers are crossed.

[turboDan]

I am almost willing to bet that one of your ign coils is on the way out.The problem is as you well know that you have 8 of them and without having a code to point you in the right direction you may have to wait til it fails completely I have seen them begin to fail on secondary side of coil and the computer never picks it up and sets a code.That is why i say you may have to wait til it dies out completely.It is hard to diagnose an intermittent problem such as the one you are experiencing while doing so over the internet and without the correct monitoring tools.