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Discussion Starter · #1 ·
Hey guys. I'm at a loss. I have a 1993 Firebird Trans Am with a 5.7L LT1. After a week of running perfectly fine, I started the car three consecutive times in a matter of about 30-45 minutes. On the third start, the car started to jump up and down in idle. It stalled many times on the road, but I was able to get her home and try to fix it. It has been over a month and here is what I've replaced and come down to.
Injectors, spark plugs and wires, TP sensor, IAC valve and connector, distributor, ignition coil, and O2 sensors.
But still, I start the car, and it stalls. I've found out that when I move around the wiring loom on the driver's side leading to the coil, ICM, temp sensor, and grounds, I always get a different result when I try to start the car.
It will change from not being able to start at all, to starting and stalling, to starting and fluttering RPM, to starting and holding near idle but dying once I hit the gas.
Any ideas?
 

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Discussion Starter · #3 ·
Hey guys, I put on a Bosch code reader and got live feed data from when the car was off and I tried starting it. Here are some of the things I found, I don't know exactly what they mean but some seem off.
  • The ECM reads 25 RPM when the car is not on.
  • The IAC position is at 146 when the car is off and drops to 25-50 when I try to start it
  • Quad drivers 1,2, and 3 are bad
  • My MAP voltage and pressure drop to 0 on start
  • Oil temperature is reading -34 degrees
  • 2nd and 4th gear switches are off while 1st and 3rd are on (this is a manual car btw)
Any help interpreting these would be appreciated.
 
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