Audi Repair: 2000 a6 4.2 misfire, mass airflow sensor, spy windows

Question
QUESTION: My cars misfire and sounds like a popping noise coming from the intake at idle. I have tried plugs, coils, new vacuum line, smoked the system and i couldn't find any leaks. I also installed a new coolant sensor because of a code. It has 130 still runs and drives great but feels a little sluggish. I was told the timing belt was done by the used car dealer i bought the car from so I'm thinking maybe a timing issue. The car also has cam sensor code and i also replaced both of them. Is there an easy way to check timing?  Thanks

Steve

ANSWER: It's possible that the cam timing is off, but then the engine would have always had this problem...  I would check the Mass airflow sensor, to really check the valve timing properly is fairly involved; there are no spy-windows to check marks.  When did the problem start?  Let me know,  Jan

---------- FOLLOW-UP ----------

QUESTION: When i bought the car the check engine light was on for a coolant sensor. I really didn't notice if it had the problem then but soon after i did the sensor i began to notice the problem. I also replaced the MAS with any luck. It also starts hard some times in the summer requiring a few tries. Thanks

Steve.

Answer
So it would appear that the problems started after you replaced the coolant sensor?  I would verify that the replacement one is correct, and probably I would verify next that there are no codes in the computer at this time.  There are numerous things that can cause a misfire.  Let me know,  Jan