P0300 P0307... Misfire Ls400 98

[scw11]

my 98 ls400 ( 50K miles ) VSC and CEL light is on since couple days ago, the autozone told me it is p0300 and p0307 -- random misfire, misfire on cylinder 7.

anyone have this problem before? any suggestions where i should start?

replace sparkplugs/wires, distributor cap,

clean throttle body...

thanks,

scw11

[SRK]

Well if it's a 98 the engine has coil on sparkplug ignition, so that narrows it down a bit. The misfire is the sparkplug itself, the number 7 coil, the primary trigger circuit to the coil, or the fuel injector or its wiring to number 7. The trick is to determine which one without throwing parts at it. Pull the spark plug first. It might be as simple as water in the plug well, or the corrosion caused by it.

[scw11]

Well if it's a 98 the engine has coil on sparkplug ignition, so that narrows it down a bit. The misfire is the sparkplug itself, the number 7 coil, the primary trigger circuit to the coil, or the fuel injector or its wiring to number 7. The trick is to determine which one without throwing parts at it. Pull the spark plug first. It might be as simple as water in the plug well, or the corrosion caused by it.

SRK,

thanks a lot, will take a look this weekend.

[SKperformance]

I have no code but the right bank rear most plug does collect some oil in the plugs area of the valve cover. I wonder if that is cylinder 7?

[scw11]

I have no code but the right bank rear most plug does collect some oil in the plugs area of the valve cover. I wonder if that is cylinder 7?

check the circuit to the coil and plug, they looks good to me. not sure it is the fuel injector problem or not since i don't know how to check it. probabbly need to bring the car to the dealer or other tech people.

anyways, thanks for all your valuable information.

Rgds,

scw11