2001 suburban LT misfire with no code

[J_Jay_B]

i have a 2001 suburban LT with a whipple. the whippletronics has been removed and bigger injectors installed and then tuned. the problem is i dont know who tuned it or what size injectors it has.

early this morning i was driving and the truck started to have a rough idle and a hesitation while creeping, almost like it has a cam, but it doesnt. the SES light flashes but when i pulled codes it doesnt show anything. the scanner recognizes the SES light, but says no codes were found. i pulled plug wires one at a time with no change in idle.

also when i turn the truck off and then turn it back on the code doesnt come back for a couple minutes, even though it still idles rough. any ideas? a code would atleast let me know which cylinder to focus on.

 

[J_Jay_B]

nevermind i did it the old fashioned way. i pulled plug wires until i found the faulty coilpack. problem solved.

 

[kschumake83]

I had to do that on mine, I had one he'll of a misfire and no code. When I pulled wires I couldn't tell the difference by sound so I watched my fuel trims on the scanner and pulled the wires. I eventually found the no. 7 plug was cracked thanks to amazon's shipping department.

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[J_Jay_B]

It kind of threw me for a loop with it didn't pull a code. I've never had that happen before.

It was super fun to replace though. I have the old side mount style blower so it sits right in top of the coil packs on the passenger side. And of course it was the cylinder 2 coil that went bad which is right underneath housing and next to the bypass valve.