98 c5 misfire after header install
Thread Starter
Heel & Toe
Joined: Nov 2016
Posts: 17
Likes: 0
From: Northern VA
98 c5 misfire after header install
I have a 98 C5 A4. I recently installed TSP long tube headers and x pipe. I removed air egr and rear o2. On first start up ran like **** till it kicked the check engine light on. I drove about 100 miles that day no problem. Next day it fires up fine Start moving and I feel a nasty misfire. I check live data on hp tuners and my bank 1 and o2 is bouncing all over the place. Replaced plugs, wires and bank 1 o2. Problem presist.
Pro
Joined: May 2014
Posts: 670
Likes: 46
From: Indiana
What do your long term fuel trims look like?
Your problem may be with your bank 2 O2 sensor since as v8srfun noted the O2 readings should be bouncing and since you only noted that bank 1 was bouncing I guess that bank 2 wasn't?
Your problem may be with your bank 2 O2 sensor since as v8srfun noted the O2 readings should be bouncing and since you only noted that bank 1 was bouncing I guess that bank 2 wasn't?
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
FIRST THINGS FIRST!!!!!!!!!!!!!!
Plain and SIMPLE.. Been There DONE THAT!
I bet you a COLD ONE! You have a CRACKED PLUG!
02 ZO6 Header install I had the EXACT SAME ISSUES!!!
Bill
Plain and SIMPLE.. Been There DONE THAT!
I bet you a COLD ONE! You have a CRACKED PLUG!
02 ZO6 Header install I had the EXACT SAME ISSUES!!!
Bill
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
If you didn't remove the plugs during the header install, there is a very good chance that you cracked a plug porcelain. BE CAREFUL.. There sharp if you decide to do the FEEL test!! Ask me how I know!! 
BC
BC
Team Owner
Joined: Mar 2001
Posts: 21,325
Likes: 3,841
From: small town in S.E Pa. PA
St. Jude Donor '03-'04
Good advice as always Bill and OUCH on the cracked porcelain.. worse than a paper cut...
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