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

A common hesitation problem?

Old Oct 14, 2003 | 06:35 PM
  #1  
Ben 94z's Avatar
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A common hesitation problem?

I know many people have had hesitation problems before just throwin this out see if anybody has a ideas or similar experiences. After about ten minutes of driving on the freeway the car starts to hesitate and jerk at all rpms. THought it might be the fuel delivery system but I replaced the fuel filter, and fuel pump, that didnt help. I also replaced plugs and wires at about 65,000 (im now at 85,000). CHecked air intake fittings to see if there was excess air coming in. Anybody have ideas or possibilities? I need to get this thing dependable for a road trip asap. THanks
Old Oct 14, 2003 | 06:44 PM
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'94 Bad A Z28's Avatar
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Have you ever replaced your Opti? When your Opti is on it's way out, the car will start to hesitate and what not after it warms up a little.
Old Oct 14, 2003 | 08:00 PM
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Is that the unit in the front of the block that the spark plug wires connect into? Any idea what an opti costs? Just spent an uneeded 200 on fuel system, just want to make sure thats the likely culprit. thanks for the info.
Old Oct 14, 2003 | 08:06 PM
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Is it *only* doing it when the car has warmed up? Hesitation in closed loop could be a bad O2 sensor. At all RPM's, even in open loop, I'd say ignition is your problem. More specifically, your opti might be giving out on you.
Old Oct 14, 2003 | 08:38 PM
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Ill look into the ignition thing, Could it be simply moisture in the tank?
Old Oct 15, 2003 | 05:40 AM
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You need to check your fuel pressure when the problem occurs. To me it sounds like your tank vent is restricted (not totally closed) and under load the fuel can't come out of the tank fast enough. Get a simple gage with a hose and tape it to the windshield. Go for a ride and see what happens. It sure is cheaper and easier than replacing the opti.

If you suspect ignition, it's simple to have a shop connect the plug wires to an ignition anilyzer (spelling).
Old Oct 15, 2003 | 07:58 AM
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Could also be the COIL or the ICM
Old Oct 15, 2003 | 08:17 AM
  #8  
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Also check your throttle acceleration cable...that doesn't sound like your problem, but it won't hurt to check. I have to replace mine.
Old Oct 15, 2003 | 03:17 PM
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I would definatly check the coil and coil wire. Although my problem was in the upper RPM range, it's a quick thing to check. Look for white powder residue on the coil, or in the wire.
O2s also seem like a good place to look. Get your car scanned at autozone or what not, see if you're throwing codes.
Hope you work it out.

Peace!
-mj
Old Oct 15, 2003 | 07:49 PM
  #10  
Ben 94z's Avatar
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Thanks for the input Ill check the coil and wire. After that I think Ill take it to see if it throws any codes. Any body know the approximate price on a new opti?
Old Oct 15, 2003 | 10:26 PM
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would a bad opti cause the car to surge(spelling)at all rpms then clears up then goes crazy but does it after the car warms up any toughts? o about 8 weeks ago i wrecked it ,i had to put a front clip on it could the wreck damaged the comp. or something bec before that it ran great
thanks steven gsx@hotmail.com
95 z 28
71 buick gsx stage 1
Old Oct 15, 2003 | 10:35 PM
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I hope you're ready to become a master hesitation troubleshooter, I know I'm turning into one since buying this car.
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