Misfiring on 5 cylinders
02-07-2017, 11:58 AM
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Misfiring on 5 cylinders Car seems to randomly misfire when its been raining and now wont start. Throwing codes P0351,P0353,P0356,P0357&P0358.
First time it cut out completely and over revved when starting as it suddenly cut in with throttle open. Then starter motor casting cracked and starter rode the flex plate. I have changed the starter and flex plate and engine started but sounded like a bag of nails. Two rocker bearings had collapsed. Changed Rockers to comp cams ones. Car ran great for a week or two now misfiring again with the codes shown above. Have checked all the coil connectors and all looks ok. Ive cleaned all the earth bolts and live feeds to the relay boxes. Car misfires badly and wont start. Does anyone have any advice, could it be crank sensor or CO2 sensor?
1998 LS1 Trans Am, Comp Cam rockers, K&N Air Filter, Borla Exhaust otherwise believed stock no other fault codes but guages go haywire when its misfiring, speedo goes fullscale low oil light comes on.
Anyone have any ideas?
First time it cut out completely and over revved when starting as it suddenly cut in with throttle open. Then starter motor casting cracked and starter rode the flex plate. I have changed the starter and flex plate and engine started but sounded like a bag of nails. Two rocker bearings had collapsed. Changed Rockers to comp cams ones. Car ran great for a week or two now misfiring again with the codes shown above. Have checked all the coil connectors and all looks ok. Ive cleaned all the earth bolts and live feeds to the relay boxes. Car misfires badly and wont start. Does anyone have any advice, could it be crank sensor or CO2 sensor?
1998 LS1 Trans Am, Comp Cam rockers, K&N Air Filter, Borla Exhaust otherwise believed stock no other fault codes but guages go haywire when its misfiring, speedo goes fullscale low oil light comes on.
Anyone have any ideas?
02-07-2017, 12:57 PM
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I highly recommend you pull your oil filter, cut it open, and look for metal. Just to make sure you don't have any more mechanical stuff to worry about.
How's your fuel pressure? You get 58 on prime? Does it hold or fall off fast?
Beyond that, grounds on the backs of the heads comes to mind as being broken or loose
Also its possible water damage to your ECU. It would be worth swapping ECU with one from a junk yard to at least not chase a faulty ECU
How's your fuel pressure? You get 58 on prime? Does it hold or fall off fast?
Beyond that, grounds on the backs of the heads comes to mind as being broken or loose
Also its possible water damage to your ECU. It would be worth swapping ECU with one from a junk yard to at least not chase a faulty ECU
02-08-2017, 06:40 AM
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Just used a multimeter to measure volt from battery to block and all ok but voltage to rocker covers is low. Do rocker covers need a good earth as i think the rubber gaskets are insulating them?