benz_addict

Hey guys I need help with this issue.
I did a head gasket job for driver side bank (burning coolant, all good now)
And even before this job it was throwing the following code:

P0155 - 02 Sensor Heater Circuit Malfunction (I'm tuned for no cats I think and running no cats)

And now:
P0155 - 02 Sensor Heater Circuit Malfunction
P0300 - Random Misfire
P0305 - Cyl 5 Miss
P0306 - Cyl 6 Miss
P0307 - Cyl 7 Miss

CEL is flashing, and missing under 950~650RPM's codes are registered

So far I've done the following:
(x)Replace driver side bank spark plugs
(x)re-check all connections
(x)Put injector cleaner and 5L of 94 gas
(x)check oil level
---- start engine ----
Still misfiring

(x) replace Secondary Air Injection switch valve
(x) check PCV and EGR for clogs on valve covers and clean them
(x) Check PCV breather tubes for clogs
(x) Check vacuum lines
---- start engine ----
Still misfiring

Please help!

Yacht Master

Did you use the spark plug wire remover tool? If not your spark plug wires may be damaged.

O-55

have you tried swapping coil packs and spark plug wires around to rule them out?

benz_addict

Thanks for the reply.
I used a 19" wrench to pry off the wires. They came off with ease. Wires look good, but should I replace them?

GT-ER

Assuming you replaced the wires in the correct order, I am 99.99999% sure that you damaged a wire or you didn't seat them all the way.

JayhawkPharmD

My vote

benz_addict

Thanks guys.
I am going to swap the wires and coil packs around to see if the problem goes to the other side.

If that doesn't work then on further research found that pre cat, sensor 1 bank 2 needs to be replaced. P0155 comes on with misfires only for this side of the bank. Fingers crossed.

AMGfan

benz_addict...Is your CEL flashing or just staying on?

GT-ER

He said flashing in the first post.

benz_addict

I've swapped 5 6 7 coil and wires to the other side and still 5 and 7 are misfiring.

Cold start it'll be fine revving around 1k rpms as soon as it drops to idle it starts to misfire random, 5 and 7 cylinders. Freeze Frame data says 550RPM's for both and random and light flashes repeatedly.

I've replaced the O2, swapped wires and coil packs, plugs and checked for vacuum leaks. Coil packs work fine on the other side. I found a small hair line crack in one of the lines I'm going to replace it.

But as of yet it's still misfiring.

benz_addict

Hypothetical question, if timing was off by 1 tooth could it be enough to cause idle misfires?

I'm thinking I check timing again for proper alignment maybe it skipped a tooth during installation of the head.

shardul

iTrader: (1)

yes check the timing it may be off a tooth.

Jakpro1

100% and it DOES happen. Will run like sheet!!

Keeping an eye on this thread as I fight my own demons over here with misfire codes.

Right now its war with a shorted O2 sensor.

benz_addict

Replaced and swapped everything there needs to be swapped or replace including fuel injectors. Replaced O2 also. Timing seems bang on. This is so weird because it's only at idle and the car pulls like a freight train.

I give up