LT1-LT4 Modifications 1993-97 Gen II Small Block V8

93 z28 cutting out when cold

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Old 12-07-2012, 12:10 PM
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Default 93 z28 cutting out when cold

Ok when I crank the car after it has been sitting for over night or while I'm at work it has to warm up really good or it cuts out. If I first crank it and try to rev it then usually it won't rev past 2 grand it'll just start cuttin out.. The new it warms up the better it gets.. Sometimes though even when it's warm and I am taking off in 1st and up through 3rd it will slightly cut out in each gear as soon as I stomp the gas.. But it doesn't do it if I go from a roll and progressively push the gas down more and more.. Could this be the ignition coil, ignition control module, throttle position sensor or the converter clogged? The previous owner said he changed the iac but I haven't looked at it to see if its dirty. Also the car idles at 1,000 rpms even when it's warmed up.. To my knowledge it doesn't have a cam.. Sometimes it does kinda sound like it may have a REALLY small one.. I know what a car with a cam sounds like. My 94 had the lt4 hotcam and it loped noticeably more than this one.. The 94 also pulled a heck of a lot harder than this one too.. So that why I don't know why this one idles at 1,000 unless there is a vacuum leak somewhere.. And if so could that be causing the stumbling? Thanks for any help!
Old 12-07-2012, 07:53 PM
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Nobody? I need help ASAP!
Old 12-07-2012, 09:52 PM
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Id certainly check for vacuum leaks. after that check for any burnt/grounding spark plug wires. Fuel pressure might be a plausible fault aswell.. Does it ever go away 100%?
Old 12-08-2012, 06:34 AM
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Originally Posted by SoxXpupPeT
Id certainly check for vacuum leaks. after that check for any burnt/grounding spark plug wires. Fuel pressure might be a plausible fault aswell.. Does it ever go away 100%?
After it warms up pretty good I can push it to floor pretty and it won't do it.. I haven't really tried stomping it though after its warm.. But pushing it pretty fast it sometimes feels like it could be possibly holding back a little.. Almost like it kinda wants to try and cut out but it doesn't. I will check for the vacuum leaks and the spark plugs wires today.. I'm thinking it could possibly be a wire or the actually plug. The previous owner told me he changed the drivers side plugs and wires but couldn't change the passengers side cause it was too hard.. I don't even know if he gapped the drivers side right though
Old 12-08-2012, 06:34 PM
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I have what sounds like the same issue. My car starts just fine when cold but does not like to go above about 2K on the tach. It has been this way since i got the car two years ago. I have always had to let the car warm up in order to drive it without the cut outs and hesitations.

I tried doing several searches to find if others have had this issue as well, most that are posted are not resolved.

I have assumed at times that the problem might be caused by the aftermarket throttle body, CAI, or possibly a bad tune from the previous owner. My car does have a slight exhaust leak due to the back bolts on the driver side exhaust manifold being broken, not sure if this is related or not being the car is in open loop when cold.
Old 12-08-2012, 06:52 PM
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Sounds like maybe an o2 sensor, works good in open loop
Old 12-08-2012, 10:21 PM
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Originally Posted by kwacasey
I have what sounds like the same issue. My car starts just fine when cold but does not like to go above about 2K on the tach. It has been this way since i got the car two years ago. I have always had to let the car warm up in order to drive it without the cut outs and hesitations.

I tried doing several searches to find if others have had this issue as well, most that are posted are not resolved.

I have assumed at times that the problem might be caused by the aftermarket throttle body, CAI, or possibly a bad tune from the previous owner. My car does have a slight exhaust leak due to the back bolts on the driver side exhaust manifold being broken, not sure if this is related or not being the car is in open loop when cold.
Mine also has a slight exhaust leak around the converter... I'm about to have it removed though..
Old 12-11-2012, 09:18 PM
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Originally Posted by kwacasey
I have what sounds like the same issue. My car starts just fine when cold but does not like to go above about 2K on the tach. It has been this way since i got the car two years ago. I have always had to let the car warm up in order to drive it without the cut outs and hesitations.

I tried doing several searches to find if others have had this issue as well, most that are posted are not resolved.

I have assumed at times that the problem might be caused by the aftermarket throttle body, CAI, or possibly a bad tune from the previous owner. My car does have a slight exhaust leak due to the back bolts on the driver side exhaust manifold being broken, not sure if this is related or not being the car is in open loop when cold.
I was gonna let you know I got my cat cut off today and the exhaust leak is fixed now and it doesn't cut out anymore when getting on the gas!



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