Baffled with '96 LT1 running rough
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Joined: Oct 2019
Posts: 2
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From: Clearwater FL
Baffled with '96 LT1 running rough Hi All! I've got a 1996 Trans Am with an LT1. It began running rough a few weeks ago. It started after my boss drove it during a heavy downpour. I took it to my local garage and the fun began. .No codes register on diagnostics. They started throwing parts- and my money - at the problem: new optispark (twice) new water pump, new plugs, wires; checked fuel injectors, fuel filter, fuel regulator, Removed and machined heads. New computer. I picked it up yesterday and within 30 minutes the problem is back. I let it cool and tried again. It runs great while cold, but starts running rough when it warms up. I know I should take it back to the garage after the money I have spent, BUT I'm not sure they have the ability to get to the issue without draining my bank account. Ideas?
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Joined: Apr 2010
Posts: 926
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From: Central Texas
Sounds like the coil may be heat sensitive and breaking down once it gets hot (warm) . try putting 2-3 washers between the coil and the mounting bracket on the head, just that much more cooling air circulating sometimes helps. You might also replace the coil with a new one if the insulation has broken down where it just wont function. Leave the spacers there though and see if your problem goes away...
I’m sure the shop would love for you to take it back so they take you for more of your money. Water pump? The hell does that have to do with a misfire? If your opti was a problem it would be that way regardless of engine temp.
As stated, simply unplug your O2’s and drive around to see what happens. Do you have any idea how old they are?
If they are bad, go for Denso O2’s instead of Bosch or even AC Delco. Jmho.
As stated, simply unplug your O2’s and drive around to see what happens. Do you have any idea how old they are?
If they are bad, go for Denso O2’s instead of Bosch or even AC Delco. Jmho.
Yup, O2'S came to my mind as well, especially since it acts dumb only after warming up (going until closed loop). I can't understand what kind of shop would go through the trouble of yanking the heads off of a C4 and had already thrown parts at it yet didn't bother to throw a set of O2's at it. My experiences with C4's is that they aren't really a picnic to work on under the hood so pulling the heads is a bitch. What a bunch of hacks.
Also, I'd check for evidence that the work you've paid for has been done. 2 opti's? There's a bar in the frame of a C4 Vette directly in front of the damper. It makes removal a MF'r and honestly when I looked at one just about 2 weeks ago it appeared to me that the engine would have to come up a couple of inches just to get the damper free which must be done to get the Opti off if I'm not mistaken. I'd also look hard to make sure the heads have been off. A reputable machine shop would've cleaned them up nicely. When you look at the heads on the car or should be evident that they've been off.
I'm saying this because it just seems really odd to me that a shop would overlook the obvious like O2 sensors and pull a set of heads that's a pain in the *** to get off.
I'm saying this because it just seems really odd to me that a shop would overlook the obvious like O2 sensors and pull a set of heads that's a pain in the *** to get off.
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