2003 g35, car only has 60,000 miles on, previous owner kept really good care of it, but recently when driving and hitting the gas the rpms jump, but the mphs aren't catching up and when it hits 40mph the speed just stays. Even when you press the gas as hard as you can the engine revs but nothing happens, the front of the car shakes and jolts a little bit. You have to let go of the gas pedal and keep trying. Seems like the gas isn't reaching the whole engine, too much oxygen, computer chip problem? Anyone else have this problem?
drc4423

 

does the engine rev smoothly?

sounds more like a tranny problem from your description.. manual or auto transmission?

 

when you press on the gas the engine really revs and you can hear it, if you don't let off the gas, the front of the car shakes, took it to the dealership to test the computer chips, bc the service engine light came on, they found nothing wrong with the computer chips, so now the light is off, but the problem still happens. Car is auto.

 

Sounds like the car is in limp mode because the MAF sensor is dead. In limp mode, max is regulated to around 40mph and rpms to around 2500.

 

that sounds good lol, any idea how that can be fixed? going to cost a lot?

 

It could be a transmission problem. You need to know what code the computer sets when the light comes on.

Also, you may want to try putting it into manual shift mode and going though the gears manually. You can get to 40 in 2nd.

 

Undo the negative battery cable and pump the brake pedal 7 times. Drive the car after that and see if the problem goes away. If that doesn't work, unplug the negative cable again, repeat the above and keep the cable off for 12-24 hours.


With the revs jumping, but the car not accelerating I have to agree with the above poster who said it sounds like a trans problem. I would check the level/condition of the trans fluid.

 

So is the tranny slipping and the shaking is the engine bouncing off the rev limiter?

Sound like a trans problem

 

It's about a $150 part and terribly easy to install. Is the check engine light on. If you can't go over 2500rpms then the engine is in fail safe mode and it's likely the MAF is bad.

 

the check engine light is off now, after the dealership checked the computer readings, but problem still happening

 

Okay, this shouldn't surprise me but it still does. You went to the stealer with a driveability problem and they solved the CEL (check engine light) and cut you loose?? Holy jeebus.

I suppose you could take it back to them and ask them to finish the job. Could be $$$ though if they screw around for days trying to figure out what's wrong.

 

Search my threads and you'll see a post I made about a bunch of dash lights going off and the car basically not moving while the revs sky rocket. The dealer pulled the pan off my transmission and found that I needed to replace the whole thing. If this is indeed your problem, the dealer will try to charge you north of $4500 for the job while I got it done locally for $1400 with a used low mileage transmission.

 

First, test what DaveB was talking about. If you can't get the revs over 2500, then it's probably a bad MAF, and a 15 minute repair. If you can get them over 2500, then it's probably a bad transmission. How long have you had it? And do you know if the tranny fluid has every been replaced?

It's theoretically possible, although extremely unlikely, that your car is still under the 6 year, 70K power train warranty. If it wasn't purchased until this time in 2004 it's still under warranty. But the dealer should have checked that out. I'd find a good transmission shop to take it to instead of the dealership for this repair. Ask them to find a good used one or get a solid quote from them to rebuild it. Or look yourself for a used one. Getting a solid, low-mileage used one online and having it shipped will still be a good deal. The $1400 figure is about right for installing a used one.

 

trannny is slipping, common on these peice of **** trannys -_-

 

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POS Trannys?? Since when are our cars mechanically pieces o' crap? My car has 156k and has always been maintained right.. still pulls hard as fawk and transmission is smooth as silk. When people have these kinds of problems at 60k it boggles my mind and makes me think someone really did something malicious (most likely not the OP) to f*ck it up.