Last time at the track the engine misfired at the end of track and mph was off. The Nitrous was low ,but gauge was still in the green. I used SCT to return to stock tune. On the drive home my A/F was 11.8 - 12.2. The CEL came on P0307. Cleared code , drove 10 miles to shop, CEL stayed out. On the Snap On scanner #7 showed misfires but note enough to set code, Long term fuel trim was adding fuel. I smoke tested intake for vacuum leak at #7 port,OK, checked compression -good- installed new plug reset fuel adaptives. Started engine and while warming up same shit happens, #7 starts to misfire and fuel trims start adding fuel, still no CEL. Plug was wet and fuel trims indicate #7 not firing. Stuck a spark tester in #7 wire and started engine. NO SPARK. My question is why with the #7 plug wire unhooked wouldn't the check engine light come on? Time to order intake gasket and pull manifold.
#7 misfire
- Thread starter spydertt
- Start date
seethrough
Member
I think if the plug wire comes loose you will get a coil related code. I would guess that if this is not happening then the plug wire is not loose but shorted somewhere. Check the area behind the heads where the wires are routed - they can get close to the exhaust.
Crazy_Pyro
Full Access Member
I just had a similar problem with mine. But was #9 cylinder. Ended up being the plug wire wore a hole into it just under the back edge of the intake. Ran a new set and dozen passes down the track and a thousand miles since with no misfires.
10-1=9
Full Access Member
Might as well order new coils & spark plug wires while your at it.
Tony has a pretty nice set of wires that I think you might like. They are thick as hell.
Installed Tony's coils and wires a while back. I'm going to remove intake and see if I pinched a wire. Already contacted Tony he's going to hook me up.
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