winder

Changed my plugs yesterday. Went from Bosh B5 to to NGK PFR6Q. Finished the job and the car started right up and ran great.
Cleaned up the tools and took the car out. Initially it ran great, after a few miles it started running rough. Like one cylinder wasn't firing. I turned around to go back home. It made it, but was running even worse by the time i got there.

Codes read multi-cylinder misfire on 1 & 4. [Note: Plugs 1 and 4 were the only two that I had to remove the connector from the spark units to get the plug boots out.]

This morning I took the plugs out of 1 & 4. Both looked clean and barely fired. I cleaned the connectors on the spark units and up inside the boot where the top of the plug touch.
The code for misfire on cylinder #1 is gone, but still get code for #4. (Shorter runs around the neighborhood) Tried swapping out the plug on 4 with one of the Bosch i pulled out. No change; still runs rough and codes on #4.
Reset codes and put NGK back in and swapped the spark units on 4 and 5. Problem stayed on #4...?

I am perplexed.... Got any ideas?
Thanks,

17th Letter

if your feeling frisky switch the connections between the two. if they are the culprit the problem will jump to the other side of the engine. oh and they aint cheap

winder

while i had to move the top of the air box to get at the right bank plugs, the connectors where not removed. I had a friend hold the airbox cover out of the way as I changed the plugs. I'l go re-check them. NOT gonna move the connectors to test because only one plug from each side had misfire, not whole bank.

B5QShip

I would have to bend and put stress on the boot/shaft of the coilpack to get them out otherwise. Not worth the 2 seconds it takes to disconnect the harness, imo.

What'd you torque the plugs to? Check the gap?

The_Jerbel (Jordan)

You crush the crush washers on the plugs?

winder

the lower portion (about 1") of the plug boots are rubber. i didn't have to bend the couple of plug boots too bad to get them off.
the only two plugs that had misfires were the ones i took the coilpacks (spark units) off: the two forward cylinders; 1 and 4. you have to take the coilpacks off when you do not take the Y-pipe out. (i didn't)

just went and did a throttle adaptation: 04 Basic Settings- 060 Throttle Adaptation.
No change.
still searching before i bring it to my local shop.

winder

Yes. then torqued to about 15lb-ft.

B5QShip

I'd check the gap on the plugs.

Have you logged misfires before you changed the plugs? Its possible this was happening b/4 you changed them. Though if you're getting a code its gotta be misfiring a noticeable amount.

Don't give up yet! ;-) I bet you can figure it out...

Chris.Ranch

The cabling just fits. The problem will follow it. My first thought was when you had misfires on 1 and 4, very unlikely you're going to lose both at the same time.

Chris

CarsonS4B5

I apologise for coming in 6 years late but I am having similar issues at the moment with my 01 B5 S4.
Did you end up finding a solution?
Cheers