1999 BMW 328 ROUGH IDLE - MISFIRE

BFANEROS

MEMBER
1999 BMW 328
6 CYL
2WD
AUTOMATIC
130,000 MILES

I have a 1999 BMW 328i with 130,000 miles on it that "ran" great. Long story short I put Marvel Mystery oil in the gas, which is alright if you don't put way to much in there and now the car idles rough, with a bad misfire, and a backfire in the intake. I have replaced the spark plugs, cleaned the injectors, cleaned the mass air meter, changed the pre cat oxygen sensors, ran Jectron fuel system cleaner, and changed the fuel filter. Still same problems with the car. What do you suggest?

5 Replies

DOCHAGERTY

MECHANIC
9,601 POSTS

This sounds like a possible coil issue. You could have the car scanned, it is OBDII compliant, and that should give you an indication of where the misfire is coming from.

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Wednesday, October 8th, 2008 AT 10:01 PM

BFANEROS

MEMBER
2 POSTS

THE CODES SHOWED ALL CYLINDERS. I TINKERED WITH IT LAST NIGHT AND I BELIEVE TO HAVE FOUND THE PROBLEM. BELIEVE IT OR NOT ITS THE HARD HOSE ON THE PCV VALVE HAD A CRACK. WITH THE CRACK BEST SEALED AS POSSIBLE LAST NIGHT IT SMOOTHED OFF AND RAN SMOOTH, THEN ON DISASSEMBLY OF IT I BROKE IT ALL THE WAY IN HALF. LOL NOW I GOTTA TAKE IT ALL APART TO REPLACE IT.

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Thursday, October 9th, 2008 AT 6:31 AM

DOCHAGERTY

MECHANIC
9,601 POSTS

Thanks

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Thursday, October 9th, 2008 AT 10:54 PM

KEVINK29

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3 POSTS

I have a similar vehicle with a similar issue. Oddly enough, this is the second round with this problem. It happened last month but lasted only 3 days and went away on its own. Now I am replacing the fuel filter (it appears it still has the original filter with 132,000 miles) and thought it needed to be done anyway.
Any thoughts?

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Wednesday, January 19th, 2011 AT 12:49 AM

DOCHAGERTY