help asap

rebelcowboy

New Member
Mar 13, 2008
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i have a new motor in my car its a 306 and i have a miss in it that i cant fix,i have put new ignition stuff,wires,etc,new injectors,i checked my vacuum its at about 18-19 at idle.i hvae no codes other than somtimes 41 and 91,and i have ran the cylinder balance test and it always passes it flashes nine,somtimes the miss is bad and somtimes its not,if i unplug my maf sensor the car seems to run better but it still misses,could my 02 sensors be bad causing the rough idle,i have replaced the driver side already,as far as the misfire i am lost and dont know wut to do.if anyone has any help im willing to try anything to find out wuts causing the miss.my old motor seemed to miss on the passenger side,like at #4 and now it seems like its on the driver side at like #6,i need some help asap.
 
first go through and one at a time un plug a cylinder from distributer cap and it should idle down then plug it back in and keep doing that all the way around till u find the one that dosnt change the idle. a friends dad had that happen in his chevelle it ended badly (he whipped a couple lobes on his cam)
 
i have tried that and it doesnt help,the miss isnt a bad miss but u can feel it,if u unplug it then its a dead miss,the miss is not constant,my plugs have like 300 miles on them,i have checked compression all at about 150,the only thing that isnt new is my coil,i think its the stock coil.
 
that might be a problem as well i would have to go get my shop manual to tell u everything u could try



coils very rarely are faulty.. you may want to isolate what system is doing this first... as for the unplugging the wires to see if its plug/wire you can also do this to injectors or get a noid light and see if there is voltage at the injectors (assuming its EFI) check your fuel pressure at idle as well.. those are a few things that might get you headed in the correct direction..
 
yea it efi,when i do the cylinder balance test with the ecm,it always passes,it doesnt miss alot at rpm's it does at idle,and it gets bad somtimes like its trying to die.could it be my stator in my dizzy?the old motor missed on the passenger side,the new one is on the passenger side,or it seems like that to me,could it be valvetrain related?i need some major help i dont want to take it to a shop.