Pulling Power - Is250 Se Auto

[Ishaq]

Hi All - Hope you are well!!

I am noticing loss of power to my car, it seems like I have lost the nippy touch when accelerating and is seriously having an effect on my enjoyment of driving my car. Before it was fast and smooth and very noticeable - now its noisy and revving hard :(

It almost feels like I have a load and very heavy almost like something is holding me back. When I accelerate it feels like the engine is revving hard and trying so much but looking at the speedometer I am still moving from 30 towards 40MPH - Strange feels like when a clutch is on it way out or something.

What I have inspected:

I have walked around the car feeling the wheels to see if there is any heat to suggest sticking callipers - They are cold no heat

I have checked all fluid levels - All okay

I have checked to see if the AUTO gears move up as they should and they are shown on the display

I have used flappy paddle shifts and they too are okay

I have used Archoil AR6400 on fill ups

I have just placed an order for BG44K

It has been happening since I changed front and rear callipers and disc's with pads. I also changed the Oil and Filter here in October 2013. I have replaced the cabin filter with OEM and I have K&N Air Filter.

Any suggestions what I can do - also I had a hydrogen engine clean last November.

Thank you

[Jamesf1]

Im no mechanic but hard revving with lack of forward momentum - sounds like a slipping clutch if its not sticking brakes.

[stevet]

Could try changing the auto gearbox oil.

[Ishaq]

Thanks guys...don't want to hear it's a gearbox issue 😔

Can it still be an issue even thou I can see the gears change smoothly on the display.

Gearbox oil change sounds good.

Also could it be anything to do with the mech putting cheap engine oil on service

[is200 Newbie]

Is it auto or manual?

Have you checked the exhaust?

[Ishaq]

Hi newbie....it's an auto

Exhaust is smoking, pretty normal in this weather right? Or is there anything I should look out for?

Should I give it another engine oil and filter change?

October I spent £1k on parts for caliper and other bit don't want a huge bill again

[is200 Newbie]

You have said its noisy - would have to ask how noisy? If your exhaust is blowing then power will be down no matter how hard you accelerate.

It will be quite easy to rule the exhaust out either by putting it on a ramp or having a look at the exhaust yourself, listening for leaks or looking for soot marks down the length of it - check especially behind the resonator (between this box and the back boxes) you may need a hand from someone to rev the engine a bit if you are looking at it yourself

What's the mileage?

I would say if its not your brakes then it could be the exhaust ... the exhaust does "smoke" in this cold weather but its only condensation and will go once the exhaust is hot. I have not heard of the Archoil, maybe someone has?

The BG44 is a treatment for the petrol system, reportedly to remove carbon deposits, used it myself with no issue and I believe myself that it has worked on mine but I cant see this producing the problem you have...

Changing the oil and filter wont have a noticeable driving difference you have described and I cant see any recommendation on the service schedule regarding changing the gearbox oil up to 110k miles

[Ishaq]

Hi Newbie

When I say it's noisy I mean in the cabin I can hear the engine revving hard - that noise. Not exhaust noise.

I might have to look at the brakes again as it does feeling like something holding me back or when slowing down. Also when starting from day before when the car roles I can hear sqeeeky noise when wheels are rolling. Maybe it's the brakes behind the wheels which I can see, but there is no exssesive heat from the wheels.

I bought another rear caliper from Lex Sheffield for £99 so will see what happens.

Can sticking brakes make the car feel like there is load in car and hold me back.

I have monitored the fuel usage and that is normal..24mpg in town and 35-9 on motorways...if it was clutch then maybe more fuel would be used

[Ishaq]

Sorry mileage is 72,000

[is200 Newbie]

Did you check the rear brake shoes IN the disc (there are pads and shoes on the back wheels) .... coming to think of it is your parking brake on? It wouldn't be the first time I have moved the car with it on .... quite easy to forget to take it off.

[Ishaq]

No the parking brake is off and no light is showing...it makes a beeping noise if it is on. I will have to check that, sound like a good place to start

[Fishboy]

My mechanic said that the brake shoes on the rear hubs can become detached from the backing material. Chock the rear up and stick the auto in neutral check the wheels rotate freely, if not that could be the problem.

[PhilipK]

What fuel are you using? If you normally fill up at the same garage, is there any possibility that they have had a bad batch?

Might be worth trying a couple of tanks of Shell V-Power Nitro+ and seeing if it makes any difference?

[Ishaq]

Hi I normally use Shell V-Power Nitro but last two fills have been at Tesco using Momentum 99 and Archoil additive.

I have been reading around so will now Fill Full Tank V-Power, Clean the MAF Sensor and inspect all other things that I can think of. Also I will reset the ECU (take off battery).

2nd I will take the car to mechanic.

Can anyone say if it is possible for the clutch to slip even thou I can see the gears go from 1,2,3 to 6 on the display or should that be effected also? What I mean is delayed

[dazed]

Can anyone say if it is possible for the clutch to slip even thou I can see the gears go from 1,2,3 to 6 on the display or should that be effected also? What I mean is delayed

Being an automatic, your car doesn't have a clutch. What it does have is a torque converter. It is possible to damage a torque converter which can result in symptoms similar to a slipping clutch, but it's very unusual and you would probably have heard something when the damage/failure occurred.

How free revving is the engine when you're driving? For example if you press the throttle down reasonably swiftly, do the revs fly up and stay there while very little power is transmitted to the wheels even after two or three seconds? Does the car drop down a gear or two as per usual or is it more likely to stay in a higher gear since the problem began?

How well does the car coast? If there is brake resistance of any kind you'll lose speed more rapidly than usual when you throttle off.

[Ishaq]

Can anyone say if it is possible for the clutch to slip even thou I can see the gears go from 1,2,3 to 6 on the display or should that be effected also? What I mean is delayed

Being an automatic, your car doesn't have a clutch. What it does have is a torque converter. It is possible to damage a torque converter which can result in symptoms similar to a slipping clutch, but it's very unusual and you would probably have heard something when the damage/failure occurred.

How free revving is the engine when you're driving? For example if you press the throttle down reasonably swiftly, do the revs fly up and stay there while very little power is transmitted to the wheels even after two or three seconds? Does the car drop down a gear or two as per usual or is it more likely to stay in a higher gear since the problem began?

How well does the car coast? If there is brake resistance of any kind you'll lose speed more rapidly than usual when you throttle off.

When I press the throttle the revvs go up and the car feels heavy like something holding me back. I have also tried thrashing is to see what happens and still the performance is not like before - There is slight lag 2-3 seconds and then car wants to move.

The car does lower revs as normal - I have been driving with the gears on display and can see they go up and down as normal - but still car feels heavy.

The car does slow down more quickly - Also another thing I noticed yesterday is that when I have the car on Drive at standstill and take the brakes off it does not roll as it used to - I mean it does but not how it use to 2-3 MPH

Maybe I need to take off all the wheels and cheek properly and also the handbrake shoes etc

[Dean8788]

My guess would of been rear brakes had seized on which seems to be fairly common on our car. Is there less lag when placing the car in PWR mode, on gear changes? Have you noticed any noises on start up, and I'm not sure if this would cause it and hope another member would know. Could the timing chain become slack and cause performance issues long shot I know but all the normal avenues seem to be explored.

[is200 Newbie]

Air filter need cleaning ?

[cidersteve]

find a gentle slope , and put the car in neutral and see how the car rolls , should find out if the brakes are binding, also for your previous post you said you were getting 23 to the gallon, my commmute is 7 miles each way and i get about 29 to the gallon so you should be getting more.

[Ishaq]

I have never got 29mpg in London local driving..max 24/25

Will try the slop and see how the car rolls.

Air filter was done last July...will take it out and inspect tonight.

No noise on start up.

Had water pump, new coolant, front caliper, discs and pads, oil and filter change October 2014...Milage is 72000.

There is a rattling/knocking noise from front drivers side...don't know what that could be. Had lower ball joint done on drivers side in oct 14. Maybe it's loose pads but even when I press the brakes the noise is still there so thinking track rod or stabiliser link.

Since I had the work done by this ex Woodford Lexus mechanic car seems to be going from good to worse. Will call him and see what he has to say....had the car three days to change the caliper and discs, said couldn't get the parts....that's enough time to.....😬

[agent_dess]

It just occurred to me but is it possible you need to get your oxygen sensors replaced??

It needs to be changed between 70-100k

[is200 Newbie]

If your sensors had gone you would have seen the dash board light up (VSC / Traction etc) These will initially be erattic (off and on) but as the sensor dies the warning lights will stay on.

The fault will be stored for reference but have you had any lights on?

[Ishaq]

Hi i have never had any lights on in this car.

Last night I filled the tank with bg44k and she'll v power. I don't think this will make a huge difference tbh. Gave it a thrashing but notice the speed drops down more rapidly then usual.

Frustrating thing is the car feels so heavy, don't feel confident at taking over anyone at this rate. Feels like I have a 1.6L escort

[agent_dess]

Then why not just take it along to Lexus and get them to diagnose the issue once and for all, save beating your head on the steering wheel ;) also just a note U would also start to lose power if the lambda sensor were past there sell by date so to speak.

[sel1402]

hi

may be worth checking turbo/air hoses for leakage

had similar prob on rover 800 the intake hose split and i lost about 20% power

les spragg