IS250 MAF Sensor

[DannyM]

Hi folks,

Said I'd make a post here regarding the IS250 MAF sensor. I've owned my 07 IS250 Sport since September last year. I've always found the gear changes quite juttery with lots of rev hang, poor throttle response pulling away, jerky at low speeds in traffic. Read lots of topics from the US mainly on the manual gearbox/drivetrain in these cars and attributed the cars characteristics to the design.

A few weeks ago I started getting intermittent faults for rich condition on both banks. Did some troubleshooting and seen fuel trims were sky high trying to lean the mix out. Given it was both banks showing rich, it was safe to say it was a calibration issue with the MAF sensor. I've had cars with faulty MAF sensors before but none had such an impact on the cars running after being replaced. Power delivery is much smoother, gear changes are no longer jerky and there's no juttering pulling away or at low speeds.

Hopefully this may be of some help to someone experiencing similar issues. I had the car on diagnostics before the MAF started giving issues and fuel trims were all perfect and no indicator a faulty sensor at all. I'd say if you're IS250 is decent age like mine with a few miles on it, its definitely worth replacing the MAF. I'd never have even thought about it only for it did eventually fault out.

Dan.

[Mr Vlad]

Excellent post Danny. Glad your car is running as it should. Its amazing what a difference a faulty/dirty MAF sensor can make. This thread reminds me when I forgot to use the MAF back in when I cleaned it and the throttle body. Car ran like a dog. 

[AFlex]

Thanks for the tip @DannyM

I just changed mine and the whole performance of the car has improved. Like you say, no error codes beforehand. So it must have been a lazy sensor due to age.

The other thing that also helped massively was replacing the fuel pulsation damper. I bought mine on jpcarparts - much cheaper than Lexus Parts Direct. Much smoother power delivery now.

[gji25]

On 5/17/2021 at 9:39 PM, DannyM said:

Hi folks,

Said I'd make a post here regarding the IS250 MAF sensor. I've owned my 07 IS250 Sport since September last year. I've always found the gear changes quite juttery with lots of rev hang, poor throttle response pulling away, jerky at low speeds in traffic. Read lots of topics from the US mainly on the manual gearbox/drivetrain in these cars and attributed the cars characteristics to the design.

A few weeks ago I started getting intermittent faults for rich condition on both banks. Did some troubleshooting and seen fuel trims were sky high trying to lean the mix out. Given it was both banks showing rich, it was safe to say it was a calibration issue with the MAF sensor. I've had cars with faulty MAF sensors before but none had such an impact on the cars running after being replaced. Power delivery is much smoother, gear changes are no longer jerky and there's no juttering pulling away or at low speeds.

Hopefully this may be of some help to someone experiencing similar issues. I had the car on diagnostics before the MAF started giving issues and fuel trims were all perfect and no indicator a faulty sensor at all. I'd say if you're IS250 is decent age like mine with a few miles on it, its definitely worth replacing the MAF. I'd never have even thought about it only for it did eventually fault out.

Dan.

Had exactly the same effect when i changed my maf sensor and air filter for a new one. Car seems alot smoother when changing gear and no lag on the throttle.

[ColinBarber]

Worth trying a clean before replacing. Here's our guide specifically for the 4.3 V8 engine models but is similar for other models too.

 

 

[Spark plug]

Mine was doing the same. Cleaned maf and air filter with carb cleaner [k&n filter]. fixed the problem and she got her oomph back.

 

[Mr Vlad]

Isn't it amazing how a scrawny piece of wire, basically that's what a MAF is made of, can affect a car.

[gji25]

5 hours ago, Mr Vlad said:

Isn't it amazing how a scrawny piece of wire, basically that's what a MAF is made of, can affect a car.

is that what Ford use ?

[stevbloxj]

Yes it would be the same with Ford. 

Two wires with a temperature sensor sitting on top. 

[Mr Vlad]

All MAFS have scrawny pieces of wire gji. I hope you're not belittling Ford. One thing my Focus wipes the floor with the is250 is taking the headlight out. 2 screws and out it pops. No need to faff about undoing the bumper and removing part of the wheel well trim. Sheesh that was a job and a half. 

[ColinBarber]

17 hours ago, gji25 said:

is that what Ford use ?

Most manufacturers use hot-wire MAF sensors these days but it may depend on the specific engine. All modern Toyota engines use them, you have to go back to the original Lexus IS200 to find one that didn't - that that didn't use a MAF sensor at all, just a MAP sensor - or further back to the LS400 / GS300 / Toyota Supra TT where they were using Karman-Vortex type MAFs.

[gji25]

3 hours ago, Mr Vlad said:

All MAFS have scrawny pieces of wire gji. I hope you're not belittling Ford. One thing my Focus wipes the floor with the is250 is taking the headlight out. 2 screws and out it pops. No need to faff about undoing the bumper and removing part of the wheel well trim. Sheesh that was a job and a half. 

Not at all mr vlad. i have owned many a ford. my favourite was a 1600e mk2 cortina

[Mr Vlad]

WOW a 1600e? Now that had a nickname if I remember right. The Blackmans Rolls Royce. Cracking cars.

There's only one car I ever had an issue with a MAF sensor. A MG ZT Diesel. BMW sourced engine but made better by Rover. After fitting the superb RonBox and a Pieburgh MAF the car ran like stink. After swapping back to a Bosch one it ran like silk. Just goes to show even a reputable company brand can make dodgy items.

Oh. I once forgot to plug the MAF back in in my beloved now gone is250 after cleaning the intake gubbins. Car ran very poorly with error lights onbthe dash. Oh silly me noticing when I had another look under the bonnet. How embarrassed I was lol.