Nissan Repair: 2001 Nissan Quest, mass airflow sensor, extreme vibration

Question
How do I test the mass airflow sensor?  If it is okay, I can use the money to replace the distributor as Von Sudderth suggested.  The gear on the bottom of the distributor is pristine but the contacts inside the cap are extremely chalky and I justed replaced it and the rotor.  The engine would start and run with extreme vibration but now it will crank but sounds like the starter is struggling to do so.  Hope you can help.

Answer
Hi John -

Lets start from the beginning. I will need to know some information. Apparently you have replaced the dist. cap and rotor. What about the plugs and wires? You say the car vibrates when it runs, does it miss at idle, and also when going up a hill or upon acceleration?

If you are having trouble starting it, you have probably run the battery down. Charge it up and try again, and get back to me so we can go on with the diagnosis - Let me know on the above -

thanks
aloha
calvin