..one more posting on a 1990 740 Auto Turbo Wagon as a first car ever.
Please help me to clarify the following problems/questions:

1) Sometimes the engine won't start. After several attempts it starts in
a strange mode with recurring vibrations. The car moves with jerks. After reshifting between R and D a couple of times the engine goes to its normal mode.

2) There is some squeaking - even when the car goes steady, no braking -
at the left front wheel with the wheel rotation frequency.

3) It turned out that there is no front muffler - pipe goes straight from the catalytic conveter to the rear muffler. Is the front muffler actually needed?
Will it significantly decrease the noise?

Thanks in advance...