Tom Serrago

thrown - 16684 multiple/random cyl misfires.

My 99.5 A4 1.8TQMS never had a coil pack issue.
The first time this happened (5 weeks ago) I pulled/cleaned the plugs and blew out the comb. chambers, reset the code and it was fine,and ran great. Figured I just got a bad batch of gas.
I'm thinking this time that the fuel filter is/was the cause. I'm going to change it, but just wondering if there is any btdt out there with this single code and a bad fuel filter?

TIA

Tom

RKA

What plugs are you using, how many miles on them, and what's the gap set at? If they came pre-gapped, did you confirm the setting with a gapping tool?

xr4tic

The 1.8T has a tendency to foul plugs out at idle/low RPMs during cold start-ups.

Your fuel filter has nothing to do with it, unless it's happening at WOT.

Tom Serrago

they have 25K miles on them, and gap checks to around .65 on all.
They all were more gas smelly than I can recall in the past, and #2 was a bit wet. All were more sooty than I think they should be since I cleaned them last 6 weeks ago.
I don't recall a post mentioning the fuel filter causing this code either, but since it's still the original filter with 54K miles on it, I figure it's time anyway. I just wish it was in a more convenient spot.

por911

with 54k on it, you may want to change right away. Our MY 00 30v, stopped in the road at 40k because of a clogged fuel filter.

Tom Serrago

always at op. temps never when cold. As mentioned in the below post, the plugs do look more sooty than they should. Other than that, the plugs are hardly worn.
The filter is the original so I'll just replace it, I wasn't sure if the filter could have a part in this or not.

Maybe the injectors are going bad?

RKA

I think .65 translates to 0.0255". I think you need to be around 0.028-0.030". Based on your description of the plugs, it might be a good idea to start with a fresh set.

Also do a search to verify that you're using the right plugs. I can't remember the part number off the top of my head, or I would tell you.

Yippers®

Either way, I'm with you . . replace them as it is time.

Tom Serrago

I must have gotten side tracked. The cars stern is jacked up, so I'll be changing it now, sure is a hell of a place to put a fuel filter.

Tom Serrago

when still under warranty, so it's doubtful they even checked the gap.
I'll regap them to .75mm