Toyota Avalon - Slight jolting when accelerating at low speeds

[Toyollac]

Afternoon All,

Another small issue with my Avalon...

This generally happens when the car is warm, but it can happen cold. 

When I accelerate at low speeds, up to 20 kph either reversing or in drive, I get some slight jolting, about 4 - 6 times before it smooths out.  When it jolts, it feels like it looses a bit of power.
This happens maybe 1/12 times I accelerate.

Accelerating at higher speeds is not an issue, there is no jolting.

The spark plugs have been replaced, so no issue there.

Had the trans and oil done recently.

 

Anyone have this issue before in their Avalon?  I know there can be a multitude of different potentials, but I was wondering if someone else has experienced this in their Avalon?

It's got approx 128,xxx ks. 

 

Any help would be awesome 🙂

[Tony Prodigy]

Sounds like it's surging. When was the last time you had the fuel injectors checked ?

[Toyollac]

No idea, just bought the car recently.

I'm gonna go try out some Penrite fuel system cleaner when I fill up next, see if that makes any difference. 

Will report back in a few days.

[TommyM]

On 11/7/2021 at 2:43 PM, Toyollac said:

Afternoon All,

Another small issue with my Avalon...

This generally happens when the car is warm, but it can happen cold. 

When I accelerate at low speeds, up to 20 kph either reversing or in drive, I get some slight jolting, about 4 - 6 times before it smooths out.  When it jolts, it feels like it looses a bit of power.
This happens maybe 1/12 times I accelerate.

Accelerating at higher speeds is not an issue, there is no jolting.

The spark plugs have been replaced, so no issue there.

Had the trans and oil done recently.

 

Anyone have this issue before in their Avalon?  I know there can be a multitude of different potentials, but I was wondering if someone else has experienced this in their Avalon?

It's got approx 128,xxx ks. 

 

Any help would be awesome 🙂

I had a similar issue not long ago. I replaced both the oxygen sensors because one was dead. Wasn't throwing a fault code suprisingly but the circuit was probably still good. I completely decarbonised the engine. Cleaned the throttle body, egr, etc.

 

Also replaced spark plugs & put new leads.

Been running flawlessly since. I replaced the fuel filter (in tank) & it actually picked up a bit more hp because the one in it was blocked as f**k 😂😂

 

Another thing worth mentioning. Were the correct twin tip platinum plugs used ?

They run a waste spark system. Personally i stuck with original Denso spark plugs.

Edited November 11, 2021 by TommyM

[Toyollac]

Yes, the twin tips were used, I made that point when I bought the car in 🙂

So the sparkulators have been replaced, I've put in a bottle of Penrite injector cleaner, 75ks in and no change so far, so it doesn't appear to be the Injectors.

When I bought the car it was fine, and I always put in 98, so the oxygen sensor could deffs be a potential.

I'll be bringing it in for an oil change late December, so I'll get some engine cleaner through it, fuel and air filter done etc... unless it get's worse, in which case I'll get it looked at ASAP - I don't think it's detrimental to the engine, just slightly annoying.

Odd that it only happens at low speeds.  I wonder if the surging will start to be seen at higher speeds?  

In better news... my 1974 Riviera is running smooth as a whistle!  Thought I'd share a picture (just picture it as an Avalon)

[TommyM]

44 minutes ago, Toyollac said:

Yes, the twin tips were used, I made that point when I bought the car in 🙂

So the sparkulators have been replaced, I've put in a bottle of Penrite injector cleaner, 75ks in and no change so far, so it doesn't appear to be the Injectors.

When I bought the car it was fine, and I always put in 98, so the oxygen sensor could deffs be a potential.

I'll be bringing it in for an oil change late December, so I'll get some engine cleaner through it, fuel and air filter done etc... unless it get's worse, in which case I'll get it looked at ASAP - I don't think it's detrimental to the engine, just slightly annoying.

Odd that it only happens at low speeds.  I wonder if the surging will start to be seen at higher speeds?  

In better news... my 1974 Riviera is running smooth as a whistle!  Thought I'd share a picture (just picture it as an Avalon)

It can actually be detrimental because if an O2 sensor is dead, it will default to a universal fuel trim strategy (aka rich) which will end up giving you oil dilution before the next service. They're easy enough on the Avalon to replace. I also nailed mine by doing testing, including multiple WOT pulls, noticeable flat spots in areas, etc. Now it pulls clean & hard all the way just over 6000rpm under WOT without any dead spots. I've also fitted a catch can as a preventative measure with the correct separator not the cheap steel wool special. 

[Toyollac]

I'll be calling the mechanic tomorrow.

Will update soon.

[TommyM]

14 hours ago, Toyollac said:

I'll be calling the mechanic tomorrow.

Will update soon.

Good luck !

Even the ignition coils could be possibly breaking down. I've been lucky with mine being original with over 250k, i've always ran 98RON in it because i know how anal the 1MZ's are & how sensitive they can be. Minimum should have been 95RON in my opinion like the Lexus ES300 (non VVTi)

[Toyollac]

Fixed this with a bottle of Penrite Injector cleaner - after about 150ks it started to improve, 400ks later, totally gone.  Happy days!  Just seemed they were a bit gummed up.

[TommyM]

34 minutes ago, Toyollac said:

Fixed this with a bottle of Penrite Injector cleaner - after about 150ks it started to improve, 400ks later, totally gone.  Happy days!  Just seemed they were a bit gummed up.

Running minimum 95RON in these 1MZ-FE's does keep them substantially cleaner. Along with long highway runs periodically

The Nulon injector cleaner is better stuff, stronger concentration using less. Trust me

 

Fresh oil change & atleast a 400km highway only run, cruise control & she'll clean up a bit more