I have a 89 Iroc tpi 305. I been doing alot of work to the engine and the car runs great but I was at a stop light when the car just shut but I put it in park and turned right on but the engine light did not stay on. So I went to check for codes and nothing came out so I had my mechanic test my ECM but he couldn't get any info so I'm wondering what else can I do to see if I have a bad ECM or connection. And I wanna mention that when I I turn on headlights my dash lights go out and after couple of minutes they come on does this sound like a short or bad ground?

 

Have you tested the alternator for power drop ?

 

I tested it but it's not dropping at all the alt and my battery were chcked and both are good

 

sound like the positive battery cable at the starter.

 

And I tought It might have to do something with the starter because once I replaced the starter it started acting up and my mechanic told me it's something else but ever since he switched my starter the problem started

 

sometimes its as easy as wiggling it or moving it and then re-tighten the bolt. careful when u move it ,only touch the insulated cable.

 

So do u think that's what is causing it. I'm not home but I'll check it out when I get home

 

I checked it and it was good but I did see a cable that connects to a sensor that was broken and I see where it connects toO but the harness connection is broken and I don't know what kind of connection it can be. It's right under the engine dipstick and it looks like a sensor but I don't kno what sensor it can be?

 

That would be the knock sensor.

 

It's not the knock sensor its on the engine block but at the bottom

 

I think it's the tempature switch?

 

knock sensor