Throttle won't respond when accelerating hard

[marchewitt]

Hi all,

First time on this forum since I just replaced my 2000 M Coupe with a 2006 M3 that I bought yesterday. It has 59K miles on it. I bought the car out of town and relied on a prepurchase inspection by a well-regarded local independent shop, so I never drove it until after I bought it. But after I picked the car up I discovered a major (to me) problem with the throttle.

On the drive home (all highway) I took it very easy with the car and didn't notice anything weird, but driving through town, when I gave the car some harder throttle I noticed there is definitely something wrong. As soon as the RPMs started climbing (at about 4500 RPM), the car stopped responding to additional throttle and acted as if I was only giving it about 1/3 throttle, even when the gas was pressed all the way to the floor.

This issue seems to be very consistent (I repeated it several times over during three separate trips): if I don't give the car more than about 1/3 - 1/2 throttle, no problem. But if I give it much gas, it will pull to about 4500 RPM, then there is an audible drop where the amount of throttle falls sharply to about 1/3 throttle and stays fairly steady (RPMs climb, but very slowly), even while the gas is pushed all the way to the floor.

I noticed the "service engine soon" light was on after the first time it happened, so I used my Actron code reader to try to pull any error codes. The codes I got were:

P0057 - Heated Oxygen Sensor, Heater Control, Circuit Low Bank 2, Sensor 2
P0031 - Heated Oxygen Sensor, Heater Control, Circuit Low Bank 1, Sensor 1
P0051 - Heated Oxygen Sensor, Heater Control, Circuit Low Bank 2, Sensor 1
P0037 - Heated Oxygen Sensor, Heater Control, Circuit Low Bank 1, Sensor 2

These may be new codes because the PPI report from Monday said there were no error codes present.

I am taking it to my local shop Monday for an inspection II, so I will have them check for fault codes while it's there using the BMW machine, but I'm very annoyed at having paid a premium for a low mileage car and having a PPI by a good shop, only to have a problem like this as soon as I get it.

Any input would be greatly appreciated.

-marc

[dworthy]

The oxygen sensor should last 100k on a M-3. I am thinking that you should contact the P.O. and inquire about this issue, but I don't think there is much recourse beside leaving a bad review if you purchased this car thru Ebay or such.

Was the exhaust replaced with an aftermarket one?
When you cleared the codes, did they come right back?

[marchewitt]

I already emailed the seller (a high-end used car dealer) and have gotten no response. I'm especially frustrated with the shop that did the inspection, since I volunteered to pay double their asking price for a PPI to make sure it was thorough. I called them afterward to ask if they'd noted the issue, and they hadn't.

I asked if they'd given the car much throttle during the PPI and the guy's response was no, they don't want to "abuse" the cars. Seriously? It's an M3 and I told him I was going to take it to the track. Now I'm just venting.

Anyway, I haven't cleared the codes, since I'm taking it to my local shop this week. I'll see what they have to say. Thanks!

[dworthy]

The best test drive in a M-3 is sideways! The dealership guy I took on my test drive was a little white nuckled in the end, but no lights so I was happy.

Yeah, that can be an issue if don't test drive the car like you stole it, and it is hard to find something driving like Mrs. Daisy.

The only other recourse you may have is talking to a lawyer.

[marchewitt]

The best test drive in a M-3 is sideways! The dealership guy I took on my test drive was a little white nuckled in the end, but no lights so I was happy. Yeah, that can be an issue if don't test drive the car like you stole it, and it is hard to find something driving like Mrs. Daisy.The only other recourse you may have is talking to a lawyer.

I am a litigation lawyer, so that might come in handy if it comes to that.But I'm going to take it one step at a time and try to figure out what the problem is first. It acts like it's hitting the rev limiter - it seems to run OK, but it just acts like I'm not giving it more throttle when I am. Even sitting still and idling, I can floor it and it will waver between about 3500 and 4000 RPM and I can hear it cutting out like the rev limiter is kicking in.Any thoughts? Thanks.

[dworthy]

Have them take a look into the ABS/DSC ECU, as this can cut the motor too. Are there any lights on the dash besides the SES light? Of course if there is a code stored for EML or such, it will keep the car from reving too high.

[marchewitt]

Looks like it's fixed. My local shop said the fuse for the O2 sensors was blown, and it blew again when they replaced it. They started looking and found that the wiring for the O2 sensor was pinched under the valve cover, creating a short. Once they repaired the wiring and got it out from under the valve cover, it's been acting fine.

I had the inspection II done at the same time (including valve adjustment) and it's like night and day compared to before.

Thanks for your input!