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sprinkles08, ASE Certified Technician
Category: BMW
Satisfied Customers: 22827
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
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BMW Runs Rough With Massive Power Loss.

Customer Question

I installed a supercharger on my 2003 BMW M3. I did the required break in period and then I attempted to make a pull in 1st and 2nd gear. In 2nd gear, I hit 7500rpms, and then the car immediately started running rough. I thought it might be my spark plugs, so I replaced them with copper ones, then I did a fuel pressure test, and the fuel pump came up bad, so I replaced the fuel pump, as well as the fuel filter, fuel pressure regulator and throttle position sensor.
Car starts, but still runs rough, and sounds as if it has cams, which it doesnt. Car drives, but lots of shaking, and rough under acceleration. I then ran possible codes, and all ignition coils came up bad. So I replaced them, and then the car wouldn't stay running. It will start, but will die immediately. I put my old ignition coils back on, and then it starts and stays on, but continues to run rough.
What is the problem?
Submitted: 10 months ago.
Category: BMW
Expert:  sprinkles08 replied 10 months ago.

Hello and welcome to JustAnswer!

If the problem started abruptly while it was at high RPM then there may be an internal engine issue such as valve train damage.

The first step in diagnosing the problem is to use a scan tool to see what fault codes are setting and testing can be done from there.
Do you know what codes are currently setting?

Customer: replied 10 months ago.
The codes that are coming up are all 6 cylinder ignition coils misfiring
Expert:  sprinkles08 replied 10 months ago.

What P codes are currently setting?

Customer: replied 10 months ago.
There are no P codes popping up. They are codes 17, 18, 19, 32, 33, 34
Expert:  sprinkles08 replied 10 months ago.

I don't have any reference for codes in that format. All vehicles sold in the US 1996 and later are required to report codes in the standard P code format, a P and four digits. Whatever you're reading the codes with should (has to) display them in this format also.

Customer: replied 10 months ago.
K don't know what to tell you then. I have a tune on my car, from ESS Tuning, and with their diagnostic software, I scan the codes, and those are the codes coming up. What would the "P" codes be for cylinder misfire?
Expert:  sprinkles08 replied 10 months ago.

Do you have an actual scan tool or code reader available?

Customer: replied 10 months ago.
There are no codes present on my scanner. There are no pending codes either.Is it possible that I might have a boost leak? Would a code pop up if something was damaged internally?
Expert:  sprinkles08 replied 10 months ago.

A boost leak isn't going to cause anything but a lack of power.

The engine light is not on?

Customer: replied 10 months ago.
Engine light is not on. Could a bad crankshaft position sensor cause this?
Expert:  sprinkles08 replied 10 months ago.

It's posible for a crank sensor to cause a misfire.