94 BMW318i convertible Check Engine Light & rough starti

1.8L 234072 kilometers the car has been mostly problem free with regular oil changes and inspection done as required.(The last oil change was done on Mar 10 at 233459 kilometers)

On Apr 9 I took the car was in as the brake warning light had come on; the check engine light was also on - my mechanic checked both and both the wiring and the instr cluster were ok - no faults and the pads had 30% left ;
On sunday, when I started the car it sputtered but when I held my foot on the accelerator it stopped; I did not think anything of it as the car had not been driven for a week - also it had been very damp and rainy albeit the car had been in my garage during that time. After the car warmed up and I had driven for a bit, the car turned on and off as usual; I then drove the car agin onTuesday and it was fine; yesterday morning (Wednesday), when I started the car, it did the same thing - it was rough starting and sputtered and I this time had to really hold the gas pedal down or the car would stall out; I noticed that the check engine light came on and stayed on (again!). So I put the car back in the garage.

I am going to take the car in to my mechanic today but, I wanted to know for own info what is going on with my car. Can you help me?

Also, I noticed that on Sunday when I drove it on to the highway I really had to step on the gas to get it to accelerate to highway speed - in fact it revved to almost 5000 before it switched gears -- is that normal or just me used to driving my husband's more powerful 535i ?

Thanks