djdepot

Hey there! For the sake of not being long winded i will keep it short ,

2015 is250 has been in and out of dealers and independent shops, and the circus called carmax. 8 times

Problem is that it falls on its face when you accelerate from a stop. and the best way i can describe is that it feels like someone is holding the ebrake when i give it gas from a stop, then with no rhyme or reason it will snap out of it and accelerate quickly . witch can be dangerous in intersections ect.

it has had the tank drained of fuel and replaced, maf cleaned then replaced,1 injector replacement , and 2 codes cleared ( the dealer said they didnt record the codes, just cleared them?)

I am familiar with the adaptive transmission and the reset procedure, but that should not have to be performed every..single..day.

I just need help or somewhere to look myself. Fully comfortable working on the car my self and mechanically inclined.

arentz07

This sounds like carbon buildup, perhaps? What kind of gas do you put in the car? It would be good to get an OBD scanner and see what codes, if any, remain. I'm not a 250 owner so maybe someone who is could chime in...

djdepot

That is one thing I haven't done , I can check the throttle body / upper intake ,thank you !

djdepot

And for what its worth if the symptoms dont go away on there own ,i pull the ecu and efi fuses and it drives fine .

pngo

If it is driving fine right after you reset the ECU, the car is adapting to the conditions as it re-learns. I would also look to check the throttle body to make sure it is clean and actuating properly.

Has the dealer done any leak checks?

djdepot

ok great i will for sure check the throttle body tonight. ,and the dealers / shops have not done a leak test.

pngo

Has the dealer logged any data on their laptop when the problem happens? They should be able to monitor fuel trims and/or O2 sensor to see if the engine is running rich or lean. If a leak is reducing flow past the MAF, then the engine would be running rich before it corrects itself then go lean right before the car gets power back.

Also, after 8 trips without a solution, I would look into lemon laws in your state.

djdepot

no , being that we cant recreate the issue on cue they keep brushing me aside and just jumping to conclusions that turn out to be not the problem . but i have a scanner that can read live data that i will try on the way home .

jay90011

iTrader: (23)

It sounds like you have carbon buildup issues with the engine. Coming from a previous IS250 owner I had the same experience where the car would die for a moment when accelarating and then pick up speed after. How was the idle on the vehicle at a stop light while in drive? Did the rpms ever fluctuate to the point it would almost stall?

djdepot

The idle at a stop seemed to be normal , no shaking or shuddering , but as soon as I try to accelerate there is little to no response to the point of people beind ne honking / ect. Until I almost floor it to get it going . Also chugs/ jerks a little while cruising at like 40mph at no load .

NickCaesar

How do you reset the transmission? By pulling those 2 fuses?

djdepot

yes ,with my research it seems like the way to do it . Is there another way that you know of short of another dealer visit?

pngo

The shuddering makes me think it could be the torque converter. Does your RPM go up and does the engine sound like it’s working when you’re “stalled”?

djdepot

the best way to put it is unresponsive , like no correlation between the gas pedal position and the rpms . so the rpm doesn't really move.

pngo

Nevermind then, it seems like the engine is not getting enough air (perhaps fuel) and should probably follow checking-up on the carbon build up/throttle body.