Mass Air Flow Sensor Problem

[babylexy]

Hi everyone,

I was wondering if anyone can help me out with a problem I have been having with my 2003 IS300. A lot of times when I press the gas, the car does not move until I press the pedal several times. Some days it is so bad that I cannot even go straight through an intersection, because the car is hardly moving when I'm pressing the gas. My mechanic told me to try cleaning the mass air flow sensor. I did that, and the car feels a little bit better, but the problem is still there. I am thinking about buying a new sensor, but before I do that, I was just wondering if anyone has experienced this same problem or if anyone knows what to do about it.

[smooth1]

Hello, and welcome to the LOC.

I would start with the basics first. I would start with looking at the throttle cable and the throttle body, make sure there isn't to much play in the cable at the throttle lever there. There should be a little play, but if it's more than that you may need to adjust it tighter.

Beyond that point before going into more possibilities, I think I would need more of a description of what is going on. LIke is the motor revving and not going anywhere? or no revs and not going anywhere? So if you press the gas pedal, what does happen mechanically? Because if your getting RPM's and not going anywhere, well, that could be a transmission issue, clutch if it's a manual or torque converter if it's an auto. If your not getting any rpm's then it could soemthing in the throttlebody.

[babylexy]

Thanks for your reply..I had someone look at the throttle cable, and it seems fine.

When I press the gas pedal, there are no revs and im not goin anywhere. The rpms stay between 1-2. It lasts for several seconds, and then the car picks up and goes. My car is automatic. Do you think it could be the mass air flow sensor?

[smooth1]

No, I don't think that is your problem as the MAS reacts to, not initiates throttle, which seems to be your problem. I would continue to look at the throttlebody. It has to be in there somewhere. If you start the car and pop the hood, reach to the back of the motor and blip the throttle with the throttle lever by hand. Maybe do a full pull with it and see how the motor reacts. If you still have the same issue, it has to be the throttlebody, or maybe fuel pressure regulator, or something along that line.

[babylexy]

ok, thanks a lot for your help and suggestions

[RLis300]

Wow...my car is kinda having the same problem. If I gradually get on the gas it speeds up but if i step on it, its like,"get off me!" LOL. Its hesitating and I KNOW this car has more power than this, especially if Im trying to get down. Makes me miss my turbo civic now..

It threw these CEL code : P0171 & P0174

P0171: Fuel trim bank one condition; The PCM recognized a rich or lean condition on one engine bank only.

P0174: Fuel trim bank two condition; The ECM has detected a rich or lean air/fuel ratio condition on engine bank two.

Possible Causes:

1. If bank one and two codes are set together, suspect fuel pressure or MAF (Mass Air Flow) Sensor.

2. Oxygen Sensor

3. Ignition misfire condition - repair

4. Fuel injector problem

5. Engine Mechanical Problem.

Its easy to rule out the things you KNOW that are not possible...

In my case #5,4,2 I believe are not the problem.

Seeing that the codes are at the same time, #1 would be a great start.

A MAF Sensor is 79.99 at your local automotive stores and usually have them in stock.

I have not changed mine yet but I'm going to clean it first and see if that works.

[smooth1]

Sounds like a logical starting place. I don't know about being able to to use the local auto parts store MAS, but so long as it is the same MAF, then ok.

Let me know if it does fix it or not. I don't think it will solve the throttle issue though. It may take care of the cel you have. Don't forget, it's a drive by wire system. I actually think that is the delay you may be expereincing.

[lenore]

Hi everyone,

I was wondering if anyone can help me out with a problem I have been having with my 2003 IS300. A lot of times when I press the gas, the car does not move until I press the pedal several times. Some days it is so bad that I cannot even go straight through an intersection, because the car is hardly moving when I'm pressing the gas. My mechanic told me to try cleaning the mass air flow sensor. I did that, and the car feels a little bit better, but the problem is still there. I am thinking about buying a new sensor, but before I do that, I was just wondering if anyone has experienced this same problem or if anyone knows what to do about it.

Did you disconnect the battery after the cleaning and then connect back after about 10 minutes. This way the car relearns...

[babylexy]

REPLY TO RLis300:

ya, it sounds like we have the same problem. for now i have just been pressing the gas gradually and the car reacts a lot better to that kind of driving.

did you clean it yet? if so, did you notice a difference?

im probably going to try getting the new sensor in a couple of months. let me know if you get a new one and what happens.

[RLis300]

Yes, I cleaned it and reset the light but that didnt change anything. Soon as the engine noticed the MAF problem it threw the same code again. I even tried 93 octane with some booster and still nothing. I will just buy the sensor asap and let you know.

REPLY TO RLis300:

ya, it sounds like we have the same problem. for now i have just been pressing the gas gradually and the car reacts a lot better to that kind of driving.

did you clean it yet? if so, did you notice a difference?

im probably going to try getting the new sensor in a couple of months. let me know if you get a new one and what happens.

[babylexy]

Yes, I cleaned it and reset the light but that didnt change anything. Soon as the engine noticed the MAF problem it threw the same code again. I even tried 93 octane with some booster and still nothing. I will just buy the sensor asap and let you know.

my car doesnt have any lights that came on/come on when its having that problem. what light comes on in your car?

[babylexy]

Hi guys,

so i bought a new MAF sensor and installed it. i also got the rear wheel diff done. my car seems 96% better, but it still hesitates sometimes when i am stopped and then i accelerate. i dont know what else to do to solve this problem completely.

[RLis300]

To answer your previous question....My CEL (Check Engine Light) comes on and throws P0171 and P0174.

I was having the same thought about changing the rear diff fluid and getting a new MAF sensor.

I would also tell you to check your transmission fluid level and maybe change it. I checked mine and it was way too much in it. So that may be one reason for the shifting problems... I just drained it and going to get some more fluid tomorrow.

I'm also going to change the rear diff fluid to Royal Purple along with all my other fluids eventually.

Hi guys,

so i bought a new MAF sensor and installed it. i also got the rear wheel diff done. my car seems 96% better, but it still hesitates sometimes when i am stopped and then i accelerate. i dont know what else to do to solve this problem completely.

[babylexy]

To answer your previous question....My CEL (Check Engine Light) comes on and throws P0171 and P0174.

I was having the same thought about changing the rear diff fluid and getting a new MAF sensor.

I would also tell you to check your transmission fluid level and maybe change it. I checked mine and it was way too much in it. So that may be one reason for the shifting problems... I just drained it and going to get some more fluid tomorrow.

I'm also going to change the rear diff fluid to Royal Purple along with all my other fluids eventually.

i was also thinking about checking my transmission fluid level. i got the fluid changed a few months ago, and this problem seems like it started around the same time.

i will probably take my car to my mechanic to get it diagnosed..bc i want to know exactly whats wrong with it.

its weird that we sound like we have the same problem, but my car isnt giving me any lights.

one more question for you...when i am idling, my gas meter (i dont know what the proper name for it is) says 20 litres/km. is that normal?

[RLis300]

I just changed my differential fluid today. I took it for a test drive and now my car drives GREAT. Im in love again. lol.

Today or tomorrow just start ur car and let it run a while and take it crusin for about 5 min to get it warm. While the car is running....Check the transmission fliud level. It should be in between the two notches where it reads "HOT" on the dip stick.

As far as the MPG meter. I dont even pay attention to that crap. My meter works but you cant accurately read it...well I cant. Its constantly moving depending on how you drive and does not calculate it for you. But I think it should read 0 while idling.

i was also thinking about checking my transmission fluid level. i got the fluid changed a few months ago, and this problem seems like it started around the same time.

i will probably take my car to my mechanic to get it diagnosed..bc i want to know exactly whats wrong with it.

its weird that we sound like we have the same problem, but my car isnt giving me any lights.

one more question for you...when i am idling, my gas meter (i dont know what the proper name for it is) says 20 litres/km. is that normal?

[babylexy]

well im happy for you that your car is fixed!! :)

thanks for all your advice, it is greatly appreciated

[babylexy]

i checked my transmission fluid level today, and there was too much in there! that's what my problem was this whole time...

now my car is running great

[RLis300]

WOW. Its crazy how we had the same prob. Also I replaced my MAF and that was the OVERALL problem. Now my baby is REALLY fixed. Im in love now and forgetting my BMW everyday that goes by. I get better gas mileage and WAY more power. Im a drifter/dragster so Im lovin it. :)

i checked my transmission fluid level today, and there was too much in there! that's what my problem was this whole time...

now my car is running great

[smile_apj]

WOW. Its crazy how we had the same prob. Also I replaced my MAF and that was the OVERALL problem. Now my baby is REALLY fixed. Im in love now and forgetting my BMW everyday that goes by. I get better gas mileage and WAY more power. Im a drifter/dragster so Im lovin it. :)

i checked my transmission fluid level today, and there was too much in there! that's what my problem was this whole time...

now my car is running great

Interesting end of the story. I enjoyed reading you guys conversation and keeping prob in top of your mind. Incredible.

[MarcOchoa]

Hi All! Sorry to bring this thread back from the archive, but I'm having some transmission issues and was hoping someone might be able to guide me in the right direction...

Sorry for the long winded message, but here is my issue...

Car Details:
2003 IS300 with 134k auto transmission

Possible Problem:
Overfull transmission (based off what I've gathered from forum reads)

Car Issue:
Car seems to shift fine under normal driving conditions, but when I get on it, it doesn't seem to have much power. It downshifts and the RPM's go up, but it doesn't seem to add any power to the car. I cleaned the MAF, throttle body and replaced the air filter this morning. Car seems slightly better, but still not a lot of power when it downshifts. I live up a pretty steep hill and this is where its really noticeable. Going up the hill the car struggles (badly), even when I apply more pedal (forcing it to downshift). I checked the transmission dipstick after driving for 20-30 minutes and it's about 1" too high (above the top notch on the stick) on the dipstick, which is why I'm thinking that it's having this issue from being too full and planning to drain/refill.

Any additional thoughts would be greatly appreciated!