I started my car up and would run fine for 10 mins or so before the tachometer started jumping up and down and the engine would rev really low and sounds like it was going to sall out. Sometimes when i tried to start it a few hours later or different days the engine would start freaking out right away. the I replaced the optispark 7,800 miles ago....so i tried replacing the ingnition coil and checked the wiring to the coil and everything was fine. I was thinking it could possibly be a fusible link??? bad fuel pump/filer or injectors?? When i scanned the car i get these engine codes: Code16-LO-Res Failure, Code36-Hi-Red Failure and Code42-EST Ground.i do smell gas when the engine is trying to stall out. anway here is the link to the video where u can hear the engine want to stall out. Also when i turn the key off you can hear the engine rev back up to the normal idle rpm before shutting off. I started the car twice in the video.

http://www.youtube.com/watch?v=mzXmwHh52Ms

 

Codes 16 and 36 sound like a crankshaft position sensor problem. Code 42 is a little different... Haynes manual says to "Check the wiring and connectors between the ignition module and the ECM/PCM. Replace the ignition module. *Replace the ECM/PCM*". Perhaps one problem is causing all the codes. Not quite sure.

 

could it just be the computer that needs to be re programed?? cause the car sometimes runs perfect for 10-15 mins before it starts doing what is in that video i posted.

 

I noticed there is white smoke and that it smelled like gas when the engine was messing up....meaning the car is running wayyyyyyyy to rich.....thinking its the computer possibly??? dumping too mich fuel in the cylinders or a possible crank sensor?

 

If the car is misfiring or the timing is off, you have introduced some unburned fuel to the exhaust system. This could also cause it to seem like it is running rich... I'm going to say the crank sensor. Hopefully some others will chime in with their opinion.

 

I pulled 2 of the plugs and they are all black sooty which tells me the car has to be running rich. I think it is caused from the crank sensor and the computer is not awhere of were the crank shaft is so its just dumping fuel. but i could be wrong. I was wondering where and how much a new crank sensor is and what are the steps to replacing it and installing it??

 

There is no crank position sensor on the LT1. The high res pulse (DCT 36),and low res pulse (DCT 16) come from the Optispark. The PCM uses these signals to control the ignition coil module, which in turn controls the ignition coil. DTC 42 is a problem with the Ignition Coil Module and associated wiring. If you are sure the distributor is good, you need to look at all the wiring and connectors between the Opti, PCM, ignition coil module, and the ignition coil. It would be a good idea to try a different (known good) ignition coil module.

 

i dont have any advice, but the video when its running its sounds like your cammin lol

 

i already replaced the ignition coil, but when u say ignitio coil module u are just talking about the coil right?? where u have the opti coil wire attached to it, plut the other wires.

 

after further investigation i believe my optispark is the problem......im going to run a compression and head gasket tests and replace the plugs and opti. I belive this is the right route to take.