patroick67

iTrader: (1)

Okay like the title says I am having two coil misfires. My code reader calls them coils b and coil g. I have swapped coils around and reset the code and it still continues to be at the same two coils. It is misfiring and running very poorly. I didn't have any issues with the car before I swapped out the old 10 bolt for the s60 rearend at the time I did upgrade the fuel pump to a racetronix fuel pump with the hot wire kit. At idle I have a perfect 62psi fuel pressure.

What I have checked so far is:
Fuel pressure-62psi
swapped coils-same issue same coils
pulled coil harness and tested to make sure there was no grounded out wires
changed plugs tr55 gapped at .045
changed plug wires
checked push rods

I haven't been able to drive my car for about 2 months now while I have been trying to figure out the problem. Any advice would be great as I am pretty stumped on this at this point.

Mod list for the car:
fast 92mm intake
fast stainless hardware kit
nick williams 92mm throttle body
ftp 104mm lid
k@n air filter
texas speed 100mm maf
prc stage 2.5 cnc 5.3 liter heads
arp head bolts
cometic head gaskets .040
texas speed ms3 cam
texas speed 1 3/4 stainless steel headers
texas speed off road y pipe
texas speed rumbler cat back
texas speed 7.4 chromoly pushrods
ls7 lifters
trunion upgrade
Norris Motorsports PCV Catch Can
racetronix 255 pump with hotwire kit
aem wideband
autometer single gauge pillar
UMI Tunnel Brace Mounted Torque Arm w/ DSL
UMI Perf On-Car Adj. Panhard Bar w/Poly
UMI Performance Lower Control Arms Poly/Roto-Joint
UMI Tubular 3-Point Subframe Connectors
UMI Performance Solid 22mm Rear Sway
UMI Strut Tower Brace
SLP Brake line lock Control Package
RPMSpeed Stainless Steel Brake Lines
slotted and drilled rotors
ss wheels with nt05r tires
ls7 clutch
chromoly 3.5 inch driveshaft with spicer upgrade
strange engineering s60 rearend detroit locker upgrade
35mm axles, new backing plates, standard width, 1/2 upgraded wheel studs
4.30 gears

S10xGN

iTrader: (11)

You're saying no new coils, just swapping them around and getting the failures at the same position each time no matter which coil is used at that position?

If that's the case, you have a wiring problem. Since you've checked the grounds, how about the rest of the coil harness? Checked the terminals to see if they've backed out?

jimmyblue

iTrader: (11)

This nomenclature is unusual, and I wonder how the
scan tool knows it's the coil rather than, say, the plug
or wire or even an injector at the same location.

Misfire current cylinder 1-8 can even be unreliable
as to which cylinder - sometimes off by one?

First thing I recommend is, just pull the injector
connector on any cylinder you suspect. If it's a
bad cylinder, that won't matter; if it's good, then
it will make things worse. Try them all and keep
track.

Now that you know which cylinders are actually
making trouble, try some easy things like using an
inductive timing light to see if the spark is being
delivered down the wire, use a stethoscope to
hear if the individual injector is busy, etc.

Your code might take several key cycles to move
after you swap parts anyway; if you can't monitor
current misfires with a scan tool, you want some
other way to check individual cylinder activity (or
a whole bunch of time spent forcing codes to clear
and waiting for them to reappear).

GMRL

I had an issue with coil g not long ago.
I swapped coils and checked plug wires, a many other things I cant remember.
The connector that goes from the main harness to the coil bracket was the culprit.
There was a bit of corrosion on one of the pins.
I cleaned both ends of the connector with electronic parts cleaner and a small screw driver.
Cleared up right away.

patroick67

iTrader: (1)

Thanks for all the advice guys. I will try these fixes and report back.