What does "po304 pending" mean? - PeachParts Mercedes-Benz Forum

MBD · #1 08-29-2008, 07:56 AM

I had codes run again on 99' S500. It came back with po308 misfire and po304 pending. I replaced coil in cyl 8 and auto runs great. A very small glitch sporadically with no CEL.

mbdoc · #2 08-29-2008, 08:06 AM

Means the cylinder #4 has had some misfires, but not enough to set a check engine lamp.

Takes 200 consecutive misfires OR 1000 random misfires.

Either a coil or spark plug issue.

MBD · #3 08-29-2008, 09:54 AM

I pulled #4 coil and plug..covered with oil. Others look dry. What would be the cause? I have replace gaskets (kit) recently due to oil sepage but no oil was found in any plug cyl.

mbdoc · #4 08-29-2008, 10:30 AM

Most likely. OIL doesn't cause that problem, but even the slightest trace of moisture in the oil will.

MBD · #5 08-29-2008, 11:02 AM

Thanks DOC ,I guess my question was a little misleading. What could cause the oil around the plug? Also I was recently told to run a few cans of seafoam thru the brake booster hose and leave over nite. I must say it caused many to turn their heads as I appeared as a jet leaving its tail down the highway. I was also told to change the oil once the white smoke was gone. Could this cause moister in the chamber?

mbdoc · #6 08-29-2008, 11:59 AM

Then most likely a coil...try swapping to another cylinder.