Transmission light, rough idle, and codes

[BoJeRo]

I have a 2001 X5 3.0. Just bought it 2months ago.
Last Sunday it started an erratic idle when started.
When in reverse there was quite a lag and then jerked the car back.
Transmission light came on and appeared to not engage first gear.
Has died upon starting about 4 times.

Codes read thus far:
First gear ratio
misfires on #1,2,3.
Throttle Valve Control Circuit.

About a month ago it had a o2 code which we cleared and did not reappear on the last reads.
Although the check engine light did come back on shortly after.
Had a mechanic friend read codes this week and then we got a Peake reader.
Planning on changing the tranny fluid & filter next week when the parts come in.
Trying to gather as much info before taking it in to an independent mechanic.
Any thoughts or experience?
Thanks in advance!
Jennifer

[Zulu95]

Check for leaks in the intake hoses.

[hotshark]

change the mass air flow sensor

[BoJeRo]

Thanks for your input!
I took "Betty White" up to an independent shop yesterday.
He cleared all the codes and voila! everything back to normal.
Threw some crazy lights on the way home, EML, Brakes and ABS, but those cleared when turned off and started again. Now all that came on is the SES.
He suggested changing the spark plugs, adding fuel injector cleaner, and a reprogram.
Crossing our fingers....

[Zulu95]

Sounds just like what happened to me when the hose from the MAF to the engine came loose. All it took was a couple of twists on the screw once I put the hose back on.