LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Help! Doesn't want to idle, bad missfire while accelerating from stop!

Old Dec 23, 2006 | 08:16 PM
  #1  
Wckd94Z's Avatar
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Posts: 284
From: Upland, Ca
Help! Doesn't want to idle, bad missfire while accelerating from stop!

94 Z28 88k miles
Ported heads
CC306
Longtubes
36# injectors
Etc.

Spark plugs (Autolite 106) and wires new. Opti is 1 year old, coil and icm 3 months old. IAC, MAF, O2 sensors all check out fine.

When I start the car and let it warm up on its own it settles right into an 800 rpm idle. As soon as I try to clutch out it starts choking and it takes alot of throttle to keep the car running. Thereafter the car won't hold a steady idle, dropping down to <600 rpms. The IAC kicks in and will raise the rpm back up to 800 for a few seconds if the rpms start to get really low, but then the engine starts to choke again and drop rpm.

Aside from trying to accelerate from a stop, normal driving is fine. No missfires, no hesitation, no cutting out at any rpm over 1500 or so. WOT is normal up to 6800 rpm. Car has about 1k miles since I put the heads on it and I've had no issues. I can't say when the problem started because i've been in Missouri for BCT for the last 3 months and my dad has been the one driving my car every 2 weeks or so.

Any help greatly appreciated! I'm on 2 weeks leave before going back to training and this problem is ruining my christmas
Old Dec 24, 2006 | 12:33 PM
  #2  
sssalah's Avatar
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Posts: 1,152
From: Bahrain
How much is your idle rpm set in your tune. You did have that tuned in the PCM??
Old Dec 25, 2006 | 12:16 PM
  #3  
Wckd94Z's Avatar
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Joined: Mar 2005
Posts: 284
From: Upland, Ca
idle is set at 800. Car worked perfect for the 2 weeks it was done back in August before I left. I came back and now it has this problem... Possible some debris in the throttle body? Unfortunately my cable for my laptop isn't working so I can't get a read on all my sensors...
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