1999 A4 Quattro w/1.8T Runs Rough
06-06-2006, 05:33 PM
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1999 A4 Quattro w/1.8T Runs Rough
My 1999 A4 Quattro began running rough with the Check Engine Light blinking two days ago. I changed the plugs to Denso Iridiums and the light went off after a few cycles and the car drives great. Today the car began idling rough and is severely lacking power as well as shuttering at speed. (CEL blinking again). I had the code read at Autozone and it claimed a cylinder 3 misfire. I switched the ignition coils for cylinders 2 and 3 to find the code still read a cylinder 3 misfire. Are the plugs the only thing left to check before going to a mechanic? Any other suggestions? Thanks in advance for responses.
06-06-2006, 05:54 PM
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Re: 1999 A4 Quattro w/1.8T Runs Rough
I'm no serious mechanic so I just took out the old plugs and put in the denso iridiums. Could the cylinder 3 plug be improperly gapped. The same code was read the first time the CEL came on (Cylinder 3 Misfire), before I replaced the plugs, as after. Could this be an erie coincidence? Just an afterthought.
06-07-2006, 08:14 PM
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Re: 1999 A4 Quattro w/1.8T Runs Rough
check your power output stage(ignition module). yours is most likely bad.it sends the signal to your ignition coils to fire them. its is a little module on top of your airbox assembly. it should have 2 connectors. later models have this incorperated into the actual ignition coils, but i believe yours is seperate. these go bad alot and definately cause flashing mil lights and rough running- dont drive your car like this- it will damage the cat- converter. they cost bout 400 bucks by the way. anyway to check it u need a probe with a diode in it. (a regular test light wont work) vag 1527B is the actual vw/audi tool #. -disconnect the 4 pin connector on the output stage. hook up the probe and crank the engine. the light should flicker on every terminal while cranking. your #3 terminal probably wont light up hence bad output stage
06-08-2006, 05:16 AM
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BIG SECOND!! Check plug gap before you go spending money on parts!!
Those plugs come gapped at .040, you need .028, a big difference that may be your problem!! Post back with your results!
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06-08-2006, 09:09 AM
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1st - don't drive it if the CEL is flashing. 2nd...
... did you reset the light before swapping coils? Find a VAG-COM.
Flashing CEL means the problem is more severe than a solid CEL.
Flashing CEL means the problem is more severe than a solid CEL.
06-16-2006, 05:56 AM
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Re: 1999 A4 Quattro w/1.8T Runs Rough
Your problem might be the ignitor, I have the same year and also had a rough runner with #3 coming up as misfiring. The ignitor is located on top of the airbox with 2 connectors.
Dont pay the dealer buy aftermarket.
Dont pay the dealer buy aftermarket.
