Need Help! Changed Spark Plus now...
 

I have a 98 A4 2.8 and I figured my car was due for a tune up. Bought it with 94k now has 102k miles on it. I pulled out the spark plugs and they were NGK Platinum's with the two prongs and that’s what I replaced them with, the same exact plugs. So I know my issue is not a gap problem. Also I replaced the air filter with a K&N drop in filter today so I did unhook a few things.

The Check Engine Light came on the day before but after I changed the plugs today on the first start up the engine began to shake violently, it didn't shake before, the Check Engine Light went from solid to blinking and also the exhaust note is different. I checked all the hoses and vacuum seals that may have come undone when I worked on it but everything looks fine.

The manual says the blinking light may be a problem with the Catalytic Converter.

I know I need to hook up Vag Com but I have been reading a lot of posts that say do not drive it with the blinking light so I am apprehensive about driving it to a shop or Advance/Autozone.

Any advice?????????

so it shakes but not rpms going up and down?

I wouldve checked the gap on the plugs and not assumed that they were correct or the same as the old ones. The oil on the filter could have messed up the MAF and create a misfire issue. Otherwise, I would back track all of the work you did and look for anything that is disconnected or loose. Could be as simple as a loose hose on the air box.

Spark plugs don't always come pre-gapped the right amount, so that is the first thing i would check and like AutoUnionFan said, oil getting in the MAF could be causing you problems.

To my knowledge there is no way to gap a two prong spark plug. They come pre-gapped with the protective cylinder around it from the box to prevent the gap from getting damaged from the factory. Am I wrong on this? Are there specific tools to gap a two prong plug? I only have the standard plug gapper.

Everything is connected back up, I back tracked twice.

I'll try to clean the MAF of any oil and see if that works.

The engine idles rough but does not jump in RPM's. I gave it a little gas and the shake became more violent as the RPM's rised.

Something made the CEL come on yesterday but whatever I did when I changed the plugs and air filter made it 10x worse.

you really can't regap a 2 prong plug with traditional tools. what you are experiencing is misfire when the cel flashes. i'd double check the plugs. don't drive the car or you will ruin your cats

$10 says your K&N dumped a whole bunch of oil on the MAF.

as stated, do not start or drive the car with a constant misfire.

Yeah, use Amsoil air filters, not K&N.

So should I take the plugs back to NAPA and get different ones? Single prong perhaps and what is the proper gap?

How do I get the oil off the MAF? There is a MAF sensor air flow cleaner spray I see from searching for it but will this get rid of the oil?

This article http://www.knfilters.com/MAF/massair.htm from the K&N site dismisses any possibility of Oil on the MAF causing my problem but I will try anything as I said if I can't drive it to a shop i'm pretty much on my own.

pull the filter, clean the MAF and check again w/o the filter

check that the coils are seated properly

check the connections to the coils

check coils are grounded properly

pull the plugs and make sure they arent cracked