Ive been chasing this ghost for a year.
04 Expy
Replaced plugs and coils about a year ago.
Started missing on cyl 3.
Ive been all over the internet reading about possible issues- coolant leaking into the plug, vac leak, etc. No evidence of either of them happening.
Ive replaced the new COPs with no improvement.
Last night I replaced the replacement Bosch plugs with Autolite with no improvement.
The #3 plug I removed last night was very fouled- looked like oil. Clearly its not been firing.
I pressure tested the system thinking I may have intake gasket issue- held 17 lbs pressure for hours with no leakage, so Im thinking thats not my issue.
Other possibilities:
The wire to the COP has a broken clip- it feel like its on the COP snugly, but Im going to salvage some good clips at the junkyard today and splice in a new one to see if that helps.
Maybe im not getting spark to the COP? Isnt that tested with a NOID light? I dont have one, will see if Autozone has a loaner.
When I was removing the COPs last night, a couple didnt feel like they were snug on the plug. I tried them on a plug, and some really dont seat well, or at all. So, Im not 100% confident they have a good seat- not sure how to solve that.
Thoughts? This is driving me crazy! Actually, its the wife's truck, so its driving me triple crazy.
04 Expy
Replaced plugs and coils about a year ago.
Started missing on cyl 3.
Ive been all over the internet reading about possible issues- coolant leaking into the plug, vac leak, etc. No evidence of either of them happening.
Ive replaced the new COPs with no improvement.
Last night I replaced the replacement Bosch plugs with Autolite with no improvement.
The #3 plug I removed last night was very fouled- looked like oil. Clearly its not been firing.
I pressure tested the system thinking I may have intake gasket issue- held 17 lbs pressure for hours with no leakage, so Im thinking thats not my issue.
Other possibilities:
The wire to the COP has a broken clip- it feel like its on the COP snugly, but Im going to salvage some good clips at the junkyard today and splice in a new one to see if that helps.
Maybe im not getting spark to the COP? Isnt that tested with a NOID light? I dont have one, will see if Autozone has a loaner.
When I was removing the COPs last night, a couple didnt feel like they were snug on the plug. I tried them on a plug, and some really dont seat well, or at all. So, Im not 100% confident they have a good seat- not sure how to solve that.
Thoughts? This is driving me crazy! Actually, its the wife's truck, so its driving me triple crazy.