A little background:

Two months ago I get t-boned. Resulting in damages to the passenager door (about 2" scratch), right rear quarter panel, splash guard and rear right rim. Fast track 45 days later, I get my car back from the bodyshop.

I've had the car back now for four days now and I noticed an unusual revving everytime I brake. When I initiate the breaking, it'll go down to 900 rpm and then all the sudden jump to 1300, then down to 800 and rev up to 1200. It revs two times before my car comes to a complete stop. Now here's the other problem...the check engine light just came on tonight. So for four days I've been driving with this problem and all the sudden the engine light.

It appears as though the bodyshop detailed the engine. Before I start pointing fingers, I wanted to see if any mechanic gurus could identify the problem? I am not willing to pay for a freaking diagnostic if the bodyshop is at fault but if this is covered by warranty, I'll take it to the dealer.

Thanks in advance guys!

btw...I have an 05' AT with only a K&N drop filter that was serviced 4 months ago or approximately 3500 miles ago by the dealer. Total mileage is 36k.

 

Get the code that is thrown and go from there. Auto supply shops usually have readers.

 

Do most Pep Boys or Kragen run the diagnostic free or would I have to purchase the OBD reader?

 

Here in socal autozone has the readers for use. They ask for either a credit card of drivers license to use it. You plug in read and can erase or just note the code down.

 

I just got my G back from a shop as well...mine did a similar thing, the idle wasn't going below 1200. Worried, I reset the computer (unplug the negative battery terminal, and depress the brake a few times). Problem went away.

 

I would just take it to the dealer, If u have an 04 u should have warranty till 60k miles. Just take it to the dealer let them worry about it.

 

True but I heard the owner had to pay the diagnostic fee...runs up to $150 and in this situation, the bodyshop should be at fault. In any case...I called up the shop this morning and said to stop by for a checkup. Worse case they'll take it to the dealer themselves and pay for the checkup.

 

Just keep in mind if u take it to the dealer be agressive about it, like it is their fault. If u show weekness they will take advantage of u (at least some dealers will). Good luck.

 

Alrighty...OBD came back with a faulty electronic throttle control. Dealer doesn't know if it covered under warranty but if I remember correctly, it should be under powertrain. Thanks all for the input and klubbs, I'll be sure to have my game face on when I drop by the dealer tomorrow. GRR!!

 

Jesus, the dealer's an idiot. They should have tried this first because I had the exact problem occur a few weeks back. Here's the fix and it's easy and free:

https://g35driver.com/forums/engine-drivetrain-forced-induction/190257-you-may-cause-trouble-code-p0507.html

 

Thanks Dave...I read your thread before going to the dealer and suggested this. The service adviser already thought of it before I could finish my sentence. They ran the test and it came back as a faulty ETC so they're replacing it.

 

I still think they're wrong because the issue you describe is exactly the issue I had and I'd bet $20 that the code that is being thrown is P0507. The problem is the idle is slightly high and has you slow down, the shift solenoids raise the downshift speeds slightly and you'll feel the surging and see it on the tach. The FSM says to replace the ECU or ETC which is silly because performing the three procedures listed will get the idle back to where it's suppose to be. If they're replacing the parts under warranty then it's no harm, no foul because the part will be replaced and they have to perform the three procedures. If they're making you pay for it, then I'd say get the car back and do the procedures yourself and see what happens.