The hesitates and misses is probably a chock problem, especially since when it warms up, it does great.
Since you weren't very specific on your indications, I thought a general troubleshooting guide might be helpful to you. But you might want to look on ebay for a shop maintenance manual for your vehicle if you plan on keeping it for awhile and doing your own maintenance.This
answer is applicable for many BMWs in addition to the one listed
The tach and speedo work most of the time, but sometimes
Here is a write-up on the
initial steps in tracking down a speedometer and/or tachometer
Applies to: E23, E24, E28, E30, E32, E34 with speed sensor units
mounted in the differential housing cover.
1) Speedometer - The speed sensor may be faulty. The sensor is mounted in
the differential cover. Remove the harness plug and remove the sensor. Clean
the sensor and measure the resistance (should be 0.0 Ohms). If there is any
resistance higher than 0.0 (zero Ohms), replace the sensor. If the resistance
reads correct, reinstall the sensor.
2) The wiring at the connector plug for the speed sensor (in the differential
housing) may be faulty and corroded .... pull the boot back from the plug housing
and inspect the wires and the pins.
3) The actual speedometer and/or tachometer head may be faulty. It may have a
loose connection within it or a cracked circuit board.
4) The speedometer or tachometer head may be loose on the main instrument
circuit board (do the gauges change or move if you smack the top of the dash,
above the gauges?). Remove the instrument cluster and check the mounting of the
speedometer/tachometer to the circuit board. See the attached issues of our Fast
Times newsletter for assistance in removing the instrument cluster, on E30
3-series models (see the articles on replacing the PC board and replacing the
odometer gears for info on the removal of the instrument cluster).
Fall 2005 Fast Times Winter 2004/2005
DIY E30 PC Boards DIY Odometer
5) The plug that carries the impulse signal into the instrument cluster may
have loose contacts. The plug for the speedometer signal is located on the
driver's side of the back of the instrument cluster (on the E30 chassis). If you
remove the lower dash trim panel (the one above the driver's knees), you can
reach up and touch the plug. It is in a vertical position and has up to 26 wires
in it. If you wiggle the plug, while driving, and the speedo comes & goes,
you have loose contacts in the plug connection.
6) You may have a problem with the service interval PC board and it's NiCad
batteries. If your oil change and service interval lights can not be reset (or
will not stay reset for an appropriate time period), the PC board is likely
faulty. This can affect the various gauges, including the speedometer and
tachometer. If the PC board is faulty, I would suggest replacing it (after
checking the other areas noted above). See the attached Fast Times newsletter
article on replacing the service interval PC board.
In your specific case, I would suspect that you need to replace the service
interval PC-board, if your service reminder lights can not be reset or do not