i had put up a post yesterday about missfiring.
well i have some new info...

first the car
1998 a4 1.8t fwd 150hp stock
tap stage 2 chip
2 stage BOV
k and n intake (no box)
custom exaust

here are the codes
16684 (random misfire detected)
16687 (cycl #3 misfire detected)
and
18021 (MIL Call-up - circuit open or short to b+) now this one happend after i put the test computer in that TAP sent to try and see if it was my ecu. it never came up on my ecu

here is what i did
1. moved all the coil packs around to see if it was bad and moved to another cylinder...it did not, stayed on #3
2. moved the injectors around to see if it moved to another cylinder...it did not stayed on #3
3. comperson test...all 125psi car has 80,000...that is good
4. changed all the plugs

what else could it be?
the (sorry for the lamens term) the thing that came out of the air box with the heat sink?

help please

E

 

maybe the ecu?

try this
take out the coil pack, see there there's actually spark on 3 coil pack while the car is running. also listen to teh injector on 3, see if it's clikcing. if no spark or no clicking, maybe wiring or computer.

 

tap sent a test ecu, and it was the same, i did move the packs around, and pulld the wire on 3, with no change, and there was if i pulled another..
injectors all sound good, and when i puled the rail they were all shooting


humm

E

 

wiring, that's what i think it may be too

thanks

E

 

Ignintion control module on the airbox.

 

yeah.. absolutely the ignition control unit.
some will call it Ignition Control Module.
ICU / ICM is on the air box... attached with 2 screws... it also use some thermal paste.

I had mine replaced a few months ago.
may be coincidence but my problem was cyl 3 too.
good luck

 

i orderd it last night....i hope that is it.
i will be shur to let you guys know, what happens..

E

 

well it was the ignition module
i replaced it with an aftermarket part from HUCO...is that ok???

also i am getting a coolant code
16502 or p0118(engine cooanl temp circuit -high input(low temp)
would that part make the car run soft? it feels like it has no boost????

thank all of you with the help on the ignition module

E