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

Stumbling/missing under 1700rpm

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Old Apr 30, 2008 | 09:21 AM
  #1  
always faster's Avatar
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From: Solar system/earth/canada/quebec
Stumbling/missing under 1700rpm

My car when its cold just seems to ride perfectly.If im at a red light and snap the gas in first gear the car will pull very hard.

When it begin to be hot(normal temp range) again at a red light,if i snap the gas in first gear it will miss or stumble untill 1700rpm than the car will pull hard.

I ve tried a couple of set of wire,5 opti, 2 complete plug changes,2 coils,and it still do it?

What should i look for?

Last edited by always faster; Apr 30, 2008 at 09:46 AM.
Old Apr 30, 2008 | 10:05 AM
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Originally Posted by always faster
My car when its cold just seems to ride perfectly.If im at a red light and snap the gas in first gear the car will pull very hard.

When it begin to be hot(normal temp range) again at a red light,if i snap the gas in first gear it will miss or stumble untill 1700rpm than the car will pull hard.

I ve tried a couple of set of wire,5 opti, 2 complete plug changes,2 coils,and it still do it?

What should i look for?
What happens when you are going down the road and put into a gear that bogs the engine down do you feel a skip? I have a similar problem. I changed my battery it lightend up a little bit. I changed my egr, it lightend up a little more. I am going to fix my header leak then possibly change my o2's.
Old May 1, 2008 | 09:46 AM
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From: Solar system/earth/canada/quebec
Originally Posted by Pezcore67
What happens when you are going down the road and put into a gear that bogs the engine down do you feel a skip? I have a similar problem. I changed my battery it lightend up a little bit. I changed my egr, it lightend up a little more. I am going to fix my header leak then possibly change my o2's.
Yep i feel a skip.

Headers and headers gasket are new,new battery,new o2 sensors.Everything is practicly new on the car(no kidding here).

Last edited by always faster; May 1, 2008 at 09:48 AM.
Old Jun 4, 2008 | 08:47 AM
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Bringing it back on the top because i cant seems to find whats wrong here.

Thanks for the help.
Old Jun 4, 2008 | 04:02 PM
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Kory 88 Iroc Lt-1's Avatar
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Old Jun 4, 2008 | 04:36 PM
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Faulty TPS maybe. I would get it scanned and look at all the sensor feeds.
Old Jun 5, 2008 | 08:15 AM
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Originally Posted by formulalt4383
Faulty TPS maybe. I would get it scanned and look at all the sensor feeds.
Well the only sensor that i didnt change is the TPS.Ill give it a try.
Old Jun 5, 2008 | 08:46 AM
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Do you have any way scanning the car to see what the sensors are doing?
Old Jun 6, 2008 | 06:52 AM
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Originally Posted by MEAN LT1
Do you have any way scanning the car to see what the sensors are doing?

I got TTS datamaster and it doesnt seems to be anything wrong.

If the car is really pulling over 2k rpm it means that its probably not ignition related right?
Old Jun 9, 2008 | 07:38 AM
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Ok new fact.

I ve drove the car this week end.It miss under 2500rpm when its cold or hot so the temp doesnt change anything.Its seems to have a problem when i less than 50% throttle because when i step on it it seems to be running really good.

Thanks
Old Jun 12, 2008 | 06:08 PM
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clean your mass air flow...with either alcohol or mass air flow cleaner. I had the same problem last year, completely rebuilt motor, tranny and rear, every sensor changed some more than twice. I cleaned the maf and it would run great, then a few days would pass and it would run like crap again. I replace the maf now and it runs great.
Old Jun 16, 2008 | 07:16 AM
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Originally Posted by transAMdriv3r
clean your mass air flow...with either alcohol or mass air flow cleaner. I had the same problem last year, completely rebuilt motor, tranny and rear, every sensor changed some more than twice. I cleaned the maf and it would run great, then a few days would pass and it would run like crap again. I replace the maf now and it runs great.
Ive already clean it and tried one of my freidns that was working perfectly but thanks for the input.
Old Jun 16, 2008 | 08:04 AM
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If I follow your conditions, it runs fine in open loop, but misses in closed loop. If so, that should narrow the range of culprits. It appears you have tried a number of things already. In closed loop with the Datamaster, you should be able to find something out of wack. Double check 02s. What is the reading on your ECT?
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