Vacum Leak? / Misfires / System Too Lean...(P0303 & P0308 - P0171 & P0174)

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Aug 10, 2004 | 09:18 AM

tooltime4677

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Vacum Leak? / Misfires / System Too Lean...(P0303 & P0308 - P0171 & P0174)

I have checked the other "threads" on this site regarding the "System Too Lean (Bank 1 & 2) OBD II codes, and have checked the PVC Valve connections, and still I'm having trouble with misfires on 3 & 8.

I have replaced the coil packs and spark plugs, front O2 Sensor, and still no luck.

Would it be possible (since 3 & 8 are connected through the intake manifold) that there may be a faulty head gasket around one or the other cylinder, causing the vacum leak...or lower than normal fuel pressure here?

I'm stumped!

Aug 10, 2004 | 05:04 PM

radtec

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From: Eureka Mo.

Did you test the plug wires themselves

Aug 11, 2004 | 08:14 AM

tooltime4677

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Wires

I assume that you are referring to the Coil Pack connectors, as there are no conventional Plug Wires...Yeah, I checked them all and they have current running to them.

Thanks for responding,....any ideas about the head gasket???

Aug 11, 2004 | 08:40 AM

radtec

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From: Eureka Mo.

I seemed to remember there were long boots on these from a friends truck I was calling that a plug wire. I thought I had replaced one of these one time because the current it was carrying was different from the others nearby and that solved the problem but my memory may be wrong may have been different make of truck.

Aug 11, 2004 | 08:50 AM

radtec

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From: Eureka Mo.

I have seen vacuum leaks occur due to bad gaskets on intake manifolds or plenums. But never had one off a expy just a idea.

Aug 12, 2004 | 09:17 AM

tooltime4677

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Plenum Gasket

Thanks for the idea. Just had another look and the "damp" area is on the side of the head, not the bottom, inside the plenum around cylinder #8, ...maybe the bolts came loose. I'll re-torque. It owes me nothing, as it's in great shape with 244,000 Kms on it.

Thanks Again!

Hoss

Aug 27, 2004 | 10:07 AM

tooltime4677

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Fixed!

Changed the Intake and Plenum gaskets. That fixed the Vacum leak.

Checked the Coil Pack with a multimeter, and one of them was "dead".

With a Mechanics stethoscope, checked the injectors, and found two of them not "clicking" like they should. Rplaced one coil pack and two injectors, and, low and behold, it's running like new again.

Thanks for the suggestions everybody!

Hoss