CODEPO300 RANDOM CYLINDER MISFIRE on 2004 Chevrolet Silverado 1500

HAD LOW COMPRESSION IN CYLINDER SEVEN,HAD VALVES DONE,STILL THE CODE PO300 APPEARS.RINGS OK,NEW PLUGS,WIRES ETC.,NEW INJECTORS,ERASED CODE,CODE RETURNS AFTER @ 3 KEY STARTS.NO OTHER CODES APPEAR. WHAT IS MY NEXT POSSIBLE SOLUTION TO PASS SMOG? THANK YOU

by in La Puente, CA on February 11, 2013
2 answers 6 comments
ANSWER by on February 11, 2013
did you recheck the compression after you did the work?
COMMENT by on February 11, 2013
yes compression is normal in all cylinders now. also fuel line pressure, fuel pump ok
ANSWER by on February 11, 2013
could be anything from primary ign to poss dist is set incorrectly.start by ck'ing dist alignment 1st
COMMENT by on February 11, 2013
ok thank you.could it possibly be a sensor.i.e cam or crank sensor? reason i ask about the sensors is that a cert. mechanic mentioned them to me, and it is relatively costly to replace them on my budget. thanks again
COMMENT by on February 11, 2013
yes but dist alignment is very important and will set codes on 3rd cycle
COMMENT by on February 11, 2013
can you please explain what dist. alignment is,also set codes on 3rd cycle,i would like to relay info, if possible. thank you
COMMENT by on February 11, 2013
set eng to top dead center and point rotor at #1 cyl on dist cap
COMMENT by on February 11, 2013
independent coils.no dist cap. 2004 4.8l 1500.