WELL I TOOK MY 99.5 A4 1.8T TO AN AUTOZONE AND THE SCANNER SAID "MISFIRE IN THE 3RD CYLINDER. THEY TOLD ME TO REPLACE THE SPARK PLUG AND I ALSO REPLACED THE COIL. AND MY CAR IS STILL THE SAME. ITS SHAKING WHEN I ACCELERATE. ANY IDEAS WHAT MIGHT BE THE PROBLEM???? THANKS GUYS.

 

first off, relax and dont drive the car. once you've done that. stop typing in all caps. next tell us what the code was spacifically please.

 

Have the code reset, and see if it returns.

 

if its still running bad then you need the code because autozone could be wrong, P0303 is coil/spark plug 3, yes clear the code and see what other code comes up

 

What are the plugs gapped @?

 

Also check the wires to the coils. They might be bad or burned.