Benzoxtc

Background: I just got the car back from the body shop for installation of a full body kit (bumpers, skirts, roof and deck spoiler, hood, and fenders). Prior to me taking the car in there were no shakes. While the car was in the shop the battery went dead....they probably left the doors open or the trunk is my guess.

Now, I get my car back and I notice tha it shakes shortly after I come to a stop or while it is in park...I would say 15-20 seconds after I reach a stop or am at idle. The best way to describe this problem is to imagine yourself at a stop and then all of a sudden the car starts to hesitate as if it wants to shut off. I've noticed that the shaking occurs after I start the car, roughly the 15-20 second time interval, while it idles in park, neutral, reverse and drive (with foot on brake). I then rev the engine and the shaking goes away, but then returns after a brief moment. My first guess is that perhaps a vacuum line was not re-attached properly, but I don't know where this could have happened since they did not touch the motor. I am planning to take it back to the shop, but I would like to get some ideas of what could be the problem.

Any ideas of what is causing the problem? I will post pics of my car as soon as I upload them to my computer.

Thanks in advance.

clk22

sounds like the MAF.

MarcusF

Did you get a new battery, or did they just charge the old one? If the ECU is seeing low voltage (the lowest voltage seen while running is at idle in drive), it may throw the idle off (amongst other things). I would opt for a new battery.

Also, if the ECU loses power, it will require several miles before the OBDII parameters are reset. That can throw the idle off as well. The last car I had fail smog was because the battery had been changed less than 10 miles before the test. It took about 20 miles before the ECU would cycle through the pretests.

blackbenzz

It does sound like a MAF but I dont see why that would happen. Actually yes I do. Same kind of thing happened to me. My battery died and when I drove the car afterwards i felt alot of hesitation. Replaced the MAF and everything was like new. The way it was explained to me was that the ECU was making up for the MAF on its way out. When the battery died the ECU reset and was no longer accomodating for the faulty MAF and the hesitation occured. Hope that helps.

mattr2

Can it be done outside of a service shop?

superstar

It took me 10min to change the MAF. the price is about $150-200 Online . If you go to the stealership hehe

blackbenzz

Yea but if you go to the stealership and the MAF fails again you get a new part for free. WHich is what happened with me. So I got 2 MAF's for the price of one. Just do the install yourself. Its very easy. Once you take the airbox off you will see the MAF athe back of the engine.

Benzoxtc

I did not get a new battery, the shop most likely just charged the battery. Do you think that if I drive the 20 miles or so, the ECU will reset itself? What is the voltage that I should be reading on the battery for our cars?

If I use an OBD reader will I be able to pull a code to determine if it is a faulty MAF? I just can't imagine every time the battery dies there will be a need to replace the MAF.

blackbenzz

MIne did not read a code. Im not saying that everytime the battery dies you need to replace the MAF. Im just saying the ECU adjusts for the faulty MAF and when your battery dies your ECU resets. If you change your MAF you will feel like you are driving a totally different car.

Benzoxtc

I hear ya. I will give it another week since I will be busy and if the problem persists I will take it into the stealership. Luckily I am still under warranty