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1998 Audi A-4 2.8liter

My A-4 has 63K on it. It is a great car. The plugs and wires have 5k on them. The car ran great until a few weeks ago when it the CE light came on. It now runs rough with limited power. The CE code says random misfire on #1 and 4 cylinders. Sometimes the CEL is steady other times flashing.

I replaced the plugs, and checked the wires(even though only 5K on them) I ran the car in the dark to check for any arcing from the wires or coil pack, put fresh name brand premium in the tank. I am going for the fuel filter next. Any ideas?


Bring it to a shop and maybe they can do some tests. It might save you a lot of time and money. It may beat guesswork.

This is where your repair manual comes in handy. There are three ignition coils on a plate. Each ignition coil fires to two spark plugs. #1 and #4 spark plugs may be fired by the same ignition coil (repair manual reference, please).
Swap the ignition coil with another. Have the codes erased. Drive the car for two errands (“trips”). If the trouble codes move to other cylinders, that ignition coil is defective. If the codes stay at #1 & #4, the fault is somewhere else.

Cool, great idea. I will give it a try. I’ll let you know what I find. Thanks