Hey guys, a friend of mine just stopped by because he was having a problem with his A4. Its a 1998 1.8T. The rpms wont pass 3k-3.5k and the CEL starts flashing. Sometimes it lights up solid. I scanned it and came up with the following codes:

16705 - Engine Speed Sensor (G28): Implausible Signal
P0321 - 35-10 - - - Intermittent
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 - -
16687 - Cylinder 3 Misfire Detected
P0303 - 35-00 - -
16688 - Cylinder 4 Misfire Detected
P0304 - 35-00 - -
16686 - Cylinder 2 Misfire Detected
P0302 - 35-00 - -

I cleared them a few times and they come back the minute you press the gas. sometimes the speed sensor code shows up alone, but the misfire codes show up 90% of the time. Ive heard that 1.8t's have issues with coil packs going bad, am I correct in assuming this is the cause?

 

Check the spark plugs make sure they look okay. Check the coil pack harness that plugs into the coilpacks make sure the wires arent badly damage / exposed. Try clearing the codes and swapping out the coil on Cylinder 1 and and put it into the 2 and see if the misfire jumps from 2 to 1 if thats the case its most likely the coil pack, do the same with other misfiring cylinder with the cylinder 1 coil.

 

The harnesses don't have to have exposed wires to be bad. Take your finger and try to move the inner part of the connector (the black piece that the actual prongs go into) and if it moves, you need a new connector. Gapping for your plugs should be at .032 if you are not chipped and around .028 if you are. Also, look into your ICM. Those are known to fail as well and will cause multiple misfires. So there's your list.
Check Harness Connectors
Check Plug Gapping
Check ICM
Check Coilpacks

 

I would say that all of these are related to your speed sensor. If your speed sensor is off it wont recognize that your are trying to rev up to maybe 3k and instead it would think your reving at maybe 1k and then there will be misfiring like crazy. I would start with that first. also if thats not it, unplug your maf and see if that helps

 

unplugging his maf wont help...he doesnt have a map like we do..

 

True. But if they are, they are prone to fail soon enough. I had my wires exposed and there were all still together except for like 2.. and it was the cause of misfires for me twice.

 

I thought my coilpacks were going until I noticed that the connectors were all loose and ****. Replacing them took like 3 minutes. BTW, I ordered the 4 pin connector from ecstuning and while it may look like it will work, it won't. http://www.ecstuning.com/Search/Coil_Pack/ES7405/ When I called, he said "well, Im not pulling that part available for your car." I told him that on the website it was universal...but aparently I was wrong? Strike 2 ecstuning...

 

hello audi friends i did change the coils to new ones but i am still same result do you thing i should change the engine speed sensor? because that code still keeps coming up?

thanks in advance for the help guys....