PD 306 CYL 6 Misfire

**Paulie** · 09-16-2010, 05:40 PM

98 Z28 (sorry about that)

I have been chasing down a CYL 6 Misfire, originally it was a crapped out coil. As I have now rolled 5 coils through in 12 months, I am guessing something else is up.

I do intermittently code Bank 2 Lean, and the obligatory Secondary Air Injection Codes.

Just started picking up a little Fuel Pump whine about a week ago.

Where do I start?

My thought was to work injectors back to Fuel Pump, but when that slight whine started last week, I am wondering if it is something stupid like a filter or even a FP problem.

I did do the MAS reset procedure, and do have suspicions on every sensor on the vehicle as it was previously blown and the return to OEM was shaky at best.

**Spaz** · 09-17-2010, 04:27 AM

have you check the plug to make sure it isn't cracked???

**Paulie** · 09-17-2010, 05:09 AM

Originally Posted by Spaz

have you check the plug to make sure it isn't cracked???

Yes, replaced all plugs. Number six was a little dirtier than the rest, but definately intact.

I am definately thinking of working back from the injectors and will replace fuel filter just because I have not done so since buying the car. For all I know, the original OEM filter is in that thing.

Thank you for the lead!

**Smittro** · 09-17-2010, 01:18 PM

Could be a weak coil.. Try switching it with one of the others and see if the misfire follows it..

**Paulie** · 09-17-2010, 01:46 PM

Bad injector, and questionable wiring. All better.

Thanks for the input folks. Just pulled back in from post repair run. All is well in Nudbush!

**98TransAmWs-6** · 09-17-2010, 01:48 PM

I had 2 codes for a misfire in #6 and one was the fuel injector. Although I still have one misfire code for #6. What wiring was bad for you?

**Paulie** · 09-17-2010, 02:43 PM

Originally Posted by 98TransAmWs-6

I had 2 codes for a misfire in #6 and one was the fuel injector. Although I still have one misfire code for #6. What wiring was bad for you?

I ended up replacing the ignition and fuel control system harnesses. Those dudes in Port Richie Florida, Current Performance do world class (and fast 1 day turn around) OEM harness rebuilds of any systems for any LS Motor. They have been lifesavers as I wrestled with my beast.

Best part is all connectors and mounts are OEM, so even as sorry a wrench as me can work through installs.