I've been having issues with low idle (500rpm so it's rough) at hot restart but no throttle hesitation/delay or shaky feel; and slight misfiring under load on the '93 l67. The only hint is the SES light stores code 56. Does anybody have a CSM that can tell me what is on quad driver B? I suspect idle air control valve is, but beyond that I don't know. I do know that if one device on a quad driver is failed, it can mess up the function of all attached devices, which would explain the IAC not functioning.

I think the misfire under load is due to the series 1 seems to be extremely picky about the ignition coils (the coils that worked fine on the '93 NA misfired terribly on this L67). The coils I'm using are from a series 2 l67, but they were junkyard pulls and may be suspect. It has new OEM plugs and Belden wires - so I hope I can rule them out during a night-time inspection for arcing.

Just because I tend to ramble... '93 CSM, code 56; what devices are controlled by quad driver 'B'? Thanks.

_________________
Boost addict


The Fleet:
'93 SSEi - Twincharged + manual Build thread
'97 Camaro - Top swap
'05 STS - V8, AWD, her DD
'92 Trofeo - Fair weather DD
'99 Montana - top swap 3800
'04 Sierra 2500HD - LLY Duramax

Current project:
Something cool, trust me.

Upcoming projects:
'92 Bonneville SSE
'87 LeSabre T-type
'67 LeSabre

Gone to greener pastures:
'84 Sierra Classic - Twin turbo 3800
'97 LeSabre - Top swap

RIP:
'86 LeSabre - pictures
'93 SE - L67