Has this EVER happend before????HELP
01-27-2009, 07:20 PM
#1
Has this EVER happend before????HELP I own a 2001 z28 mostly stock motor! When i shift letting off the gas it takes the next gears PERFECT but when i Power shift( hold the gas down) it throws the Random Missfire light... What would be causing this and Why only under WOT shifts? It Sputters and acts like its missing every cylinder and it KILLS HP... Its starting to scare me please any INFO on this is GOOD INFO! Thanks again CODY
01-27-2009, 08:32 PM
#6
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I'm not exactly sure what you mean by mostly stock, but my friend had turned up the line pressure in his GTO and it shifted so hard into the next gear the knock sensors would detect knock. Could be your sensors are showing a false misfire.
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01-27-2009, 09:23 PM
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Crazy **** man... my car is having almost exactly the same problem. Difference is if I shift below 6k there is no problem. If I power shift over 6 it feels like it just cuts out/bogs for a second then goes but if I let off even the slightest through a shift there is no problem. Hope you find your problem cause I've replaced my entire fuel system, plugs, wires, and had it tuned/dynoed while checking fuel pressure through one of the pulls all the way up to 6600 and everything looked ok, but it still does it when I shift 
01-27-2009, 09:49 PM
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i had that problem... turned out to be the alternator wire getting burnt and shorting out of the alternator itself.... check for stupid stuff like that, also try changing plugs and wires.
01-27-2009, 09:57 PM
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The engine stays at wot through the shift and never hits the limiter so I dont understand what is changing through the shift... I thought for a moment that maybe I was crazy and the clutch was just slipping, but it doesnt make any sense the way it's happening, and I got a couple inches of air on a launch this sunday so with that and a bunch of other reasons that was ruled out a long time ago.
01-28-2009, 04:09 PM
#15
Valve Springs? They do get "tired" after a while, and might be giving up over 6K... or less if really old, tired and weak. So when powershifting, you know you're buzzing the engine pretty good..... maybe beyond the limits of the old springs.
Hey, just a thought.....
And BTW, if the lifters get pumped up, it'll take a second or two to recover.
Hey, just a thought.....
And BTW, if the lifters get pumped up, it'll take a second or two to recover.
Last edited by Scotty_82; 01-28-2009 at 05:09 PM.
01-28-2009, 08:19 PM
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I would at least check on ALL of the the electrical **** before I pulled the engine apart... although I'm getting close to that point as well Also if your problem is in fact the same as mine then it has to be something invoved with the quick shift since the engine itself will rev high without issue
Also if your problem is in fact the same as mine then it has to be something invoved with the quick shift since the engine itself will rev high without issue
01-29-2009, 05:12 AM
#18
Yeah i can rev to the limiter and no problem when i shift a slower WOT shift but when i shift fast it does it for maybe the first 500-750 RPMs with NO power then its back to its normal self! i could always just shift slower but where is the fun in that lol Thanks everyone for your help so far!
