D2 misfire on 1,3, and 5

jhk07

Well-known member
Jul 26, 2006
618
0
Seymour Indiana
Low mileage on plugs and wires. I'm leaning on upstream o2 sensor bank 1.



Have had codes for that sensor as well, thinking now it's soo fouled up, it's causing a misfire


That drivers CAT has been fried for years (don't care, not replacing).



This misfire is intermittent, but becoming more frequent. Sound like a good start ??



Long time no post gents. Cheers
 

Swedjen2

Well-known member
Sep 12, 2018
75
5
California
I would think for the ECU to put out the proper signals, it has to be recieving good data, therefore, if one of your CATS is junk, both O2 sensors will be reading out of spec bad data and sending that to the ECU. The CAT may be partially plugged and or broken causing turbulance upstream and downstream.
I have 90 RRC and had to get one of my CATs replaced to pass emissions so I could get it registered in Calif. It was $350 for a new one and that's in San Jose...not a place known for low labor rates. With the new CAT, my hydrocarbon emissions were cut in half, the CO became unmeasureable and it idles better. The SMOG shop owner said it has the emmisions of a new Honda. 6 HHC / 0 CO. (The engine was rebuilt 15 years ago then sat for the next 13. It has less than 10K on it.) I would spring for a new CAT, then Bob's your uncle.
 

jhk07

Well-known member
Jul 26, 2006
618
0
Seymour Indiana
Hmmmm ............. Maybe beat the cat converter with a Rubber mallet first.


It's been fouled for over 100k miles. (first HG job, 2006 ish ???)




I know it's not the best way, but I just can't justify spending too much more on it.
 

squirt

Well-known member
Nov 13, 2008
795
2
Los Angeles
So what's the question here? Are you asking for advice on what to do?

It sounds like your issue is isolated to bank 1. Since you're already suspecting bank 1 O2 sensor (and apparently don't want to spend any money), I'd suggest swapping the upstream O2 sensors side-to-side. Then drive for a while and see if the misfires follow. If so, I'd recommend replacing both upstream O2's with Bosch replacements. You can be cheap and try to replace just 1 with a $15 3rd party knockoff, but you'll end up buying the Bosch sensors to actually fix it in the end, so don't waste your time.
 

jhk07

Well-known member
Jul 26, 2006
618
0
Seymour Indiana
Beat Kat with rubber mallet, then it ran in open loop a few days. No Misfire(s) since. No more open loop either after it had time to adjust.
 

mlnnc

Well-known member
Mar 23, 2008
184
1
Charlotte
Replace the upstream O2, as you plan to do. The only thing shared by all the cylinders on each side is the O2 sensor. Happened to me 4? years ago, and my truck didn't ever throw an O2 code (in that instance :)).

If you want to confirm the O2 is the problem try swapping the upstream O2s side-to-side. If the misfires move to the even-numbered bank the O2 diagnosis is confirmed.