CDNFairladyZ

Hey guys, I’ve read many forum posts and am
still stumped.

ive got a 2003 fairlady z33 (JDM spec) so while you can’t read the ecu I can pull the codes I’ve pulled code p0300 and p0350.

car started with a slight miss at idle but ran fine, the misfire is now very noticeable at idle and through throttle. Noticeable not firing on all cylinders.

I started with changing spark plugs, no improvement, then removed coils tested continuity on all and all are within range averaging around 1.4 checked spark while I had them out and all have spark.

cleaned maf sensor.

where does a guy start next?

it’s noticeable rich when running with these issues,

Dirty injector? Plugged cat? Bad 02 sensor?

im stumped so appreciate the input. Thanks!

The_Laughing_Man

iTrader: (1)

It sounds like it would be an issue with one or more coil packs but I understand you tested them. How many miles are on the car? All 6 coil packs looked great when you checked them? Also, when you put it back together did you make absolutely sure to plug the correct harness connectors into the correct coil packs?

dkmura

iTrader: (64)

Bears repeating: "Also, when you put it back together did you make absolutely sure to plug the correct harness connectors into the correct coil packs?" Getting the right plug order has been a problem for many Z owners.

CDNFairladyZ

Thanks for the reply guys, 110% positive all plugs are in the right location. As I know that’s been a issue prior for many owners.
All coils tested okay with a multimeter and checked for spark with the coil out. They also all have spark so don’t think it’s a coil issue.

140km on the car so 85,000 miles. All coils were in good shape old spark plugs all had pretty even burn on them with non of them sticking out more then another.

I should mention along with the engine light on so is the slip/vcd

Sundown72

Cam sensor? It can cause intermittent misfire as it dies. Easy fix and pretty cheap.

Battery/Alternator? A fading alternator can overdraw the battery under load and lower total potential, leading to poor spark under load.

Until the misfire is sorted, I wouldn’t worry about the fuel trim...