1999 323i need help with poor acceleration - BMW Forum

bkpiper00 · 11-12-2008, 09:25 AM

Hi, I am new to this forum. I have a 1999 323i with 140K that runs fine as long as you dont try and get on it. If you keep it below 3500 rpms it runs great and the idle is perfect at 750-800. I will say that even with it driving fine under those conditions I still get the P0420 & P0430 OBDII codes.

Now comes the problem. When I try to get on the car it starts to studder and olmost dies and the idle is very erratic. I then get misfire codes P0301,P0304,P0305 & P0306. This from what I understand means misfires in cylinders #1,3,4,5 &6. I have replaced coil #1 and all new NGK plugs and plug connectors from BMW, not aftermarket. the problem still exist.

Can a bad o2 sensor cause this? How about the codes reading catalytic threshold to low (P0420 & P0430)? if its the Cat could this cause the misfire?

Any help Please

Bryan

GRIDLOCK · 11-12-2008, 01:47 PM

Your issue sounds more like a vacuum leak somewheres. A smoke-test is in order.