Expert: Sean Halliday - 5/15/2006

Question
Dear Sean,
I have a 1997BMW 328i and she is giving hell.
I have cylinder 4, 5, 6, misfire at about 70-80 mph.
She only misfire when I accelerate hard.
I have replaced the plugs and coils about three timeswith factory coils and yet I still have the problem.
Only cylinders 4,5, and 6 misfire.
If I drive out of town on a long drive they all misfire.
After the misfire the engine runs very poorly for about 1 mile then she runs smooth again.
The car has 130,000 miles and I change the oil regularly with castrol gtx synthetic.
I only run 93 octane.
Can you help me.

Answer
did you do a scan on the engine?.did the check engine light come on?..this sounds to me more like fuel,,,,,what happened when you changed the coils?....how many miles are on this car?.......i would get a leak down test on the cylinders and also the intake manifold gasket.check the vacuum on the engine usually this will tell you a lot more.it really could be any one of 3 things,spark,fuel,,,,,compression,and one of these is breaking down,also look at the crank sensor.