GrunterNZ

I have got a shudder under light acceleration between 50 and 60 KPH when applying the gas lightly, the shudder feels like transmission or an engine miss. If you apply the gas heavily the shudder is gone. Any ideas? Also does not seem to happen at any other speed while giving it light gas eg 100kph. Only this low speed range.

jr4div2

Could be a motor mount that the engine rpm's and load at that speed causes an oscillation/resonance. This shudder? It feel mechanical or do you hear the engine missing?

2013FSport

iTrader: (2)

You might check for pending misfire codes.

Also run thr best fuel you can and add some fuel system cleaner. When was the last tune up? Plugs, filter, MAF cleaning?

GrunterNZ

I will try switching to 95 on the next fill, I had it in at the shop last week and they have put new plugs in, if anything new plugs have made the issue happen more often. The oil was changed at the same time and air filter is okay. What is MAF? The mechanic was thinking maybe its the first stages of a coil pack break down.

Gville350

iTrader: (10)

It wasn't mentioned if you've pulled any codes due to the issue. I'd assume a misfire too; and assuming the new plugs were installed correctly and they're not being fouled, then the coil packs are the next likely item on the list. Then after that, possibly a fuel-delivery issue.

MAF = mass airflow sensor. You can remove the sensor from the tube and clean it with SPECIFIC MAF SENSOR CLEANER. READ THE CAN'S INSTRUCTIONS CAREFULLY!

GrunterNZ

That's the thing, the car is almost just rolling when it happens at its worst, I will be in traffic on the way to work rolling about 60 KPH and lightly push the peddle with RPM around 1500/2000 and it starts to shudder, it feels like a miss or like its crabbing like a manual car on the clutch. When the car went into the shop the mechanic could not reproduce it. I started to google and it seems that this issue has been experienced by other IS owners, reading through though I can find what the fix for these people was. I am wondering if it has been triggered by getting the transmission fluid changed reading others with this issue.

GrunterNZ

Cool thank you I will get them to check this, no codes came up when the ECU was checked. Plugs came genuine from Toyota dealer. Cheers for your ideas with this problem.

2013FSport

iTrader: (2)

If they didnt gap the plugs proper and the problem was NOT there before you took it in, this seems a little odd.

Clean the MAF, check that all hose connections are tight (mainly between air box and throttle body) as an air leak could cause s lean stumble like this and not be so bad as to trigger a CEL.

Talking about this hose... MAF is inside the air box above the filter. With the key off, unclip the sensor so the lid is free of the vehicle.

flowrider

iTrader: (9)

^^^^Gapping the plugs is really old school. I used to do that in the OLD days Nowadays plugs come with the proper gap from the manufacturer and no manual gapping is required.

Lou

Gville350

iTrader: (10)

^Assuming the correct plugs were installed.

2013FSport

iTrader: (2)

Perhaps... when I checked New denso plugs they were all over the map. Not one of six at 0.044"... And if others do your work, well who knows what they are.

Everyone beats to their own tune. I'll continue to check the components as best possible before they are installed.
But ya, several camps saying do/don't adnust precious metal plugs. The don't camp because too many idiots F'd up their plugs doing so.... lol

Izzmeister

GCLexus

I have the same shudder in my 2014 Lexus IS 350. I have heard exactly the same thing (torque converter) as being the issue. I have 107,000 Km on my car and there was no mention of replacing the transmission fluid in the maintenance schedule. However, the dealer told me that it must be replaced every 96K in Canada. After the replacement, the shudder is gone. It has only been a week so I am keeping my fingers crossed. My question is that if it does come back, can the torque converter be replaced, or will I need a new transmission?

2013FSport

iTrader: (2)

I would definitely start with fresh fluid in the transmission. I wrote a DIY fluid flush process that I used to get over 1/2 the fluid out in session on jack stands using Amsoil.

That said, I've read on the Tundra forums where the A760 trans is known to develop a deceleration shudder with aged fluid. Worse on the non-tow equipped vehicles as they lack the external trans cooler but are to tow and likely age the fluid at much higher rate than the tow equipped vehicles.

DIY fluid flush is here....
https://www.clublexus.com/forums/is-...a760e-rwd.html

2013FSport

iTrader: (2)

I didn't notice you wrote 2014 in there. The AWD has the A760 while the RWD has something different. Which is yours? RWD or AWD?