1999 A6 2.8 - I am getting a misfire code ( P0303). I was reading other threads and they say to switch coil to see if you get a misfire code on another cilynder to check if the coil is bad.

But you just can't switch wires around, i thought if i remove the star screws on each individual coil, i can switch 2 of the 3 individual coils around reattach the wires in the correct firing order and see if I get a misfire on another cylinder, but each of the 3 coils is hard wired to the harness comming into the coil pack.

PLEASE ADVISE ON PROCEDURE TO CHECK FOR BAD COIL TO SEE IF IT IS CAUSING MISFIRE CODE P0303.

 

Just pull the #3 coil and see if theres a change. If so, its good, if not then worry about swapping. You can also check spark by using a screwdiver to gound.

 

Alot of posts say to switch the coils around to test, how do you do that if they are hard wired to the harness. You just can't just change the wires, then the firing order will be off.

 

Hardwired to the harness? they have terminals, Yours may be broken and don't look like terminals anymore, like mine. But you are supposed to disconnect the wires and swap the coils and then reconnect the correct wires to the correct cylinder.

 

Different motor. My 2.7t has 6 separate coils mounted right on top of the spark plugs. The Power Output Stages (POS aka ignition control units ect.) are combined into 2 packs of three on the air cleaner. I understand your POS's are combined into your coils.

 

3 coils in the pack on the front of the motor that have a wire under the pack covered by a plasic cover that then go to the harness.

Is their any way to check it? Does another cylinder fire the same time a #3 that i can switch the wires to?

 

Is their any way to check the coils on the 99 A6 2.8 with 3 coils on the pack.

 

Yes, but you cannot check the primary, you can only check across the secondaries. Pull the plug wires and measure - should be 8-14k ohms. Chck your plug wires too - should be 4-6k ohms. If those are ok, then we check the coil power output at the terminals.. but you need an LED tester.

 

To do the coil test switch around two spark plug wires connected to the same coil. The coil is firing two spark plugs at the same time. If you have misfire on one cylinder only this should give you indication on the coil. If the fault stays on the same cylinder then it is more likely injector. If the misfire moves to other cylinder then it is the coil.

 

What are the symptoms of a bad coil? I have the same code for my A6 that I just bought, and the previous owner said the #3 coil is bad, but the issue the car has is it will run fine most of the time, but occasionally will almost completely lose power and jerks around like it's starving for fuel. Once it also wouldn't start for me and I had to keep cranking it, again it seemed like it wasn't getting fuel. I'd think that one bad coil wouldn't cause that much of an issue.