misfire on ca18

[BlitzRPS13]

k so i have a silvia with a random misfire. Engine is a ca18det... when the problem came up.. i put new plugs in it... still misfiring... it threw code 34 knock sensor then 55.. now it's just saying 55. Coilpacks all spark when you take them out one by one and make a change in idle when removed. Coilpack harness checked over and harness ground was redone and soldered. It seems to run fine for 25 mins or so.. then it starts misfiring and it gets worse and worse... car sounds like a wrx. Compresson is 150 150 148 140. New Z32 fuel filter. Has tomei 600cc injectors, greddy t518z 10cm and Z32 maf. When it misfires the vacuum gets all weird then it just goes back to normal. I'm leaning on a coilpack dying when hot but haven't been able to comfirm it. Ignitor maybe or resistor? I believe i run ngk 6's(all canadian tire has) with a 1.1mm gap.. perhaps the gap is wrong? Help is appreciated.

[BlitzRPS13]

Anyone? Msg length.

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does it do it under boost/load only ?

[BlitzRPS13]

does it do it under boost/load only ?

No its fine for like 20 mins or so.. then it misfires at any rpm randomly... then goes back to normal.. then back to misfiring.

[[email protected]]

so when its cold its fine but after warm up it begins to misfire....
try changing out the coil packs one for one and see if that helps. i had same issue and was my coil pack

[BlitzRPS13]

so when its cold its fine but after warm up it begins to misfire....
try changing out the coil packs one for one and see if that helps. i had same issue and was my coil pack

Yea gonna try out some ca18 coilpacks a friend of mine has.

[mbmbmb23]

What engine management do you have controlling the Zmaf and injectors? Stock FPR? What shape are your vacuum lines in?

[oni jake]

hmmmm i'm gonna go ahead and say you mis-aligned your cam angle sensor. I know how much of a pain the ass those things are as I had 2 CA's a long time ago. Those things gave me so much trouble because of the "half-tooth" cracking off of the exhaust cam shaft. I also failed to align the cover that holds the CAS infront of the exhaust cam and managed to break off the spindle from the sensor. Your problems are basically the same I had. But pay attention to the spindle on the CAS because I overlooked it quite a few times trying to figure out my problems.

[BlitzRPS13]

We unclipped each coilpack one by one... #4 made no change.. replaced it and unclipped it again.. made a change in idle.. coilpack was very weak.. pretty sure its fixed now. Thanks to those who replied.