Mechanics

P0306 MISFIRE CODE

2003 Chevrolet Malibu • 110,000 miles

I have a misfire in cyl 6. I am getting spark and am reasonably sure I am getting fuel. I did a compression test and am only getting about 10psi in that cyl. I am getting 190psi in cys 2&4. Didn't check 1, 3, and 5 because they are on the back and hard to get to. The engine is a remanufactured one from Advance Auto with approx 5000k and 3 months on it. Need to know what steps to look at next: intake gasket, valves, head gasket? The car was running fine until yesterday when it began to stumble under load and the check engine light began flashing. I have not detected any antifreeze in the oil. Any help will be appreciated! Don't want to have to start driving my kid to school and work : )
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Davcla1970
November 2, 2013.



If it only has 10 psi compression then you have either a valve out of it or a badly damaged piston. Go back to advanced and see what their warranty policy is. If it is only 3 months an d5000k it should still be covered. They may have a you take it to a qualified mechanic to verify the problem. But this does not sound good.

Hmac300
Nov 2, 2013.
Thanks. I will be calling about the warranty on Monday. I think my next step is to pull the valve cover for a visual inspection valves, rocker, and anything else I can see. I'll turn it over to see if the valves are stuck or moving. Can you think of anything else they may ask while diagnosing the claim over the phone? BTW, I bought it as a long block so I just had to install hype intake and components. The rebuilder was Spartan. Have you ever dealt with them? Thanks ~ David

Tiny
Davcla1970
Nov 2, 2013.
No I've never dealt with Spartan, hard telling where they are located. You could check for a bent pushrod or wrong one installed or like a broken valve spring. The motor should have lasted a lot longer than the mileage you have on it now though.

Hmac300
Nov 2, 2013.
Problem diagnosed: pulled the valve cover and the rocker are was not bolted in. Was able to retrieve the push rod and it was straight so I thought "cool, I may be able to put this back together." When I went to clean the threads on the bolt for the rocker arm I realized what I thought was thread lock was in fact the threads from the head. So my first thought was: if I can get the pushrods back where it belongs without pulling the intake manifold and heli coil the head I can probably fix it without pulling the engine (I've only done a three engines over the last twenty years so it will be a pain.) But after I thought about it, something caused the threads to rip out so it I "fix it" I may only get a few months out of it and then I'm back to where I started. The good news it that it's not something I screwed up so it should be a pretty simple warranty claim. Problem is, time is money, if I'm gonna turn wrenches I'd rather it be my jeep than a '03malibu. Any thoughts?

Tiny
Davcla1970
Nov 2, 2013.
I tmay not have gone in all the way or the threads were screwed up when they were put in. Did you install the rocker? If not then they will probably give you another head and gaskets. But contact where you bought it first to see what they will do

Tighten the rocker arm bolts to 14 N.M (124 lb in). Use the J 36660-A in order to tighten the bolts an additional 30 degrees.
Incorrect torque will strip rocker arm bolts from head. You can use a heli coil for repair it is 8mmX1.25 but again see what warranty will cover.

Hmac300
Nov 2, 2013.