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

LT1 running rough and rough idle.

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Old Nov 7, 2010 | 07:51 PM
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Default LT1 running rough and rough idle.

im still having problems with my LT1. I replaced the battery because i went and had that tested and they told me it was bad. so i put a brand new battery in it. the first time i cranked it and it didnt fire up. so i let it sit for maybe 5 seconds with the key turned on, and then cranked it and it started right up. idled for probably 45 seconds then the idle got rough and eventually died. so i start it back up and it does it again. the 3rd time i tried it, it started up and stayed running, however, with a rough idle still. i took it down the block and when i gave it some gas, it would hesitate and stumble. the SES light is NOT comming on; so i dont think its misfiring. possibly a fuel issue? when i turn the car off, i can hear something under the hood making some sort of whining sound for maybe 3 seconds, then it shuts off. is that normal? its done it ever since i had the car. (2 years) so any help to what the issue is would be greatly appreciated! thanks.
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Old Nov 7, 2010 | 08:40 PM
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update: took the car down the block again and the SES light did come on. so im going to go to autozone tmrw and have them run the code and see what it is. hopefully that will give me some insight to what the problem is.

and i wanted to add, that it hesitates all throughout the RPM range. when i give it heavy throttle, it'll stumble and hesitate then it'll start to pick up and run better, then it'll start stumbling again. i dont know if this will help you guys find my problem, im just trying to give you as much information about it as i can.
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Old Nov 8, 2010 | 12:28 AM
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you know what it can be an engine misfire. i mean if it turns and idles rough that sounds like a misfire to me. one of your spark plugs can be not working/firing. if you have an obd 2 scanner you can get the code and it will tell you what bank or cylinder is misfiring. if you do not have a scanner go to a mechanic you trust who has a scanner and tell him you just want the troubleshoot codes and you look for the codes online to tell you what the codes mean.hope that narrows your search bro. clean lt1 by the way.

Last edited by 323steel36; Nov 8, 2010 at 12:43 AM.
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Old Nov 8, 2010 | 02:45 PM
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got codes P0171 and P0174 which means bank 1 and 2 systems are lean. did research and it could be because of a dirty MAF or a vacuum leak.
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Old Nov 12, 2010 | 11:12 AM
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most likely try first the dirty maf sensor but be careful when you clean it, do not touch or damage the wire on it. dis arm the whole thing till you only have the circle fence by itself and clean it.
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Old Nov 12, 2010 | 11:29 AM
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3 key factors that make an engine run. Fuel/Air/Spark. Test your fuel pressure, check all the ignition components, and look at your intake system.
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Old Nov 12, 2010 | 03:15 PM
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i am having the same problem man! i figured it out though. do what i did, look under the hood when it is dark outside and look to see if anything is arking. i have a bad spark plug wire so im gona do plugs and wires. hope this helps dude. i checked my fuel pressure to, it was 40 psi when key was on engine off, 35psi idle
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