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Hi all,

I just recently purchase a 94 Trans Am 6-speed LT1. It has 109,000 miles on it, and has recently had the following replaced in the last 6 months:

Tires

Optispark

Water pump

Autolite Wires

ACDelco plugs

Valve cover gaskets

Exhaust manifold gaskets

Rear brakes/rotors

I am having an issue with a misfire(or what feels like a miss) and a rough idle ONLY when the car reaches operating temperatures. It gets so bad, the car shakes when accelerating at almost any RPM. However, it has basically NO power under 18-1900 RPM no matter where the pedal is. Once it hits 2000 RPM, it takes off like a rocket.

This car has plenty of power, and runs smoothly before it warms up. (With help from Gary) I was able to get an adapter to use the Scan9495 app that GaryDoug wrote. The TPS is giving correct information, and no sensors are absent. However the SVS light comes on intermittently for code 63. When the car is acting up, and the SVS light comes on, the car automatically starts acting normal again.

I am going to swap which side the O2 sensors are on, to see if the PCM starts reporting a different code. I'm hoping the Opti isn't going bad, but it does have a warranty on it.

Any suggestions? Troubleshooting steps?

Car Automotive parking light Wheel Tire Land vehicle
 

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Did the problem exist BEFORE you replaced all those parts?

Have you previously provided me with a Scan9495 data log to review?

DTC 63 indicates an open circuit on the Bank 2 O2 sensor. When the code sets, the PCM defaults to "open loop". It is logical that it will run better. You indicate it runs fine cold, and when it starts up it is in open loop.

Have you looked in the factory service manual for troubleshooting info on this code? Volume 2, page 6E3-A-114

Unlikely that the Opti would cause this code.
 

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Did the problem exist BEFORE you replaced all those parts?

Have you previously provided me with a Scan9495 data log to review?

DTC 63 indicates an open circuit on the Bank 2 O2 sensor. When the code sets, the PCM defaults to "open loop". It is logical that it will run better. You indicate it runs fine cold, and when it starts up it is in open loop.

Have you looked in the factory service manual for troubleshooting info on this code? Volume 2, page 6E3-A-114

Unlikely that the Opti would cause this code.
The previous owner replaced everything but the rear brakes and exhaust gaskets (I did those). Oh, and i forgot to mention he replaced the fuel pump as well.

I couldn't find the service manual on this site, and unfortunately i only have a Haynes manual (mostly for torque specs). Do you have it on shbox.com?

I have not yet been able to data log with scan9495 yet. I'm still figuring out how to do it.
 

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