first of all quick question how many o2 sensors does a 98 a4 2.8 have?... now for the bad part...this morning i started driving my car and it would not go past 3rpms... it was shaky . it actually fely like the intake was off or mass airflow sensor was disconected. but that all seems like it works fine.... so we sprayed starting fluid on the air intake thinking that maybe the fuel pump was not working correctly or the fuel filter was bad...spraying the intake filter actually fixed the problem...well almost. but definetly felt better.. any ideas on what it can be ?.. am i on the right track?

 

Maybe try cleaning the MAF? did you get a CEL or any other indicator light? Have you had the ECU scanned for any codes? Not all of them will turn on a check engine light.

The V6 has four O2 sensors - two before the cats and two after.

 

im going to chek the maf and scan it now that i have time...the lights that come up are "service", a bulb comes up, one thats kind of a circle, and the one that looks like the oil one... but um pretty sure that one is the oil temp sensor because that gauge isnt working.

and ive scanned the car with the obd2 and the codes i got were all o2 related because i dont have cats and an exhaust leak........

 

If the codes were only related to the second sensor on each bank it's ok, because the second sensor only checks the efficiency of the first one. If the codes are related to the first sensors then you might have to do something about this because this sensor tells the ECU about the A/F ratio. About the exhaust leak, do you still have the code?

 

one last thing how many cats are on a 98 a4 2.8L quattro?

 

2 cats & 2 sensors on both