jackalrs

2009 5.3L silverado throwing a misfire cylinder #6 also check engine light flashes and the traction light come on and i think it was stable track service light. changed out coil and wire but no change still have the light and a mis with hard shifting going to put plugs in tomorrow but have reservation on it fixing the problem any help..

tech2

swap the number 6 plug with a plug from a cylinder that's firing. if the misfire stays on #6, check compression on cyl 6. if its low, remove the valve cover, disable spark so it will crank over but not start.... see if the rocker arm is moving . If not the afm lifter has collapsed.


the afm lifters are on cyl 1, 7, 4 and 6.

jackalrs

well i changed plugs and check compression got 175psi on 6 and 180 on 2, so went sprayed around intake looking for vacuum leak did not find anything.. what vacuum lines are there that inline with cyinder 6 to make a misfire? is there a transmission modulator on the newer trucks? where could i get a vacuum hose diagram from with good detail thanks for the reply

tech2

typically a vacuum leak concern is only present at idle. at higher rpms vacuum leak problems disappear as the large volume of incoming air and drop in manifold vacuum overcome the vacuum leak.


I would check for spark with a proper spark tester. Just because you change a plug and coil doesn't mean spark it present.

jackalrs

well to update everyone on whats going on with my truck, and want to say thank you to who responded to my post, i ended up taking the truck classic chevrolet owasso oklahoma they have been super they discovered that i had a issue with the cam and when they got deeper into the engine found some scoring on number 6 cylinder wall so they are replacing the engine and should be picking it up today or tomorrow..