P0302 (cyl 2 mis), p0155 02 (b2,s2)
 

This is mainly just to document my progress in trying to figure this out, and of course to help others in similar situations.

History- 2001 chevy blazer xtreme. 120k
Bought it with a massive internal coolant leak from the intake manifold gasket into the oil valley. Was in the middle of doing the intake manifold gasket, until I saw how bad it was and decided to go ahead and do the head gaskets, got a valve job done, hot tanked the whole 9yards.

Parts replaced while doing head gaskets:
All gaskets above heads
Pushrods
Accel coil, cap and rotor
Wires
Plugs
Water pump,hoses,thermo.
Air filter
Drive belt
Coolant temp sender


Current problem:
Bad misfire at idle with code p0302
Also have code p0155

At rpm she's smooth
Getting to rpm she stumbles
Idle-bad misfire, random, not consistent, idle will drop 2-300 rpms (so from 500-300) not a good feeling lol

Swapped the maf over from my 96-no change

I'm going to change the o2 sensor this week, see what that does
If that doesn't do it, gonna pull the plug and see what's going on(mind you this ignition system haven't even been used for for an hour of on time so I'm thinking something other then ignition considering it had a rough idle/misfire before I changed everything and everything I changed made no difference)

From there I'm leaning towards injectors stuck open or slow from gunk
Just my thoughts



Any input,thoughts, ideas are greatly appreciated
Thanks for your time

i would pull that #2 plug and see what it looks like. leave the sensor alone until the miss is figured out. if its wet you could have an ignition issue or an injector sticking. could also have a valve spring issue or a valve seat not sealing. run a compression test, cranking and running if you have access to a tester