Weird stuff! I drove my car fine for a whille and then one morning when I started up the car it idled very rough and it was very low like 400 rpm and black smoke was comming out the pipes. The only thing i did was 2 days before this I have flushed the radiator and replaced the main hoses , also replaced the wiper motor and pump. I haven;t really looked at the problem but before I do i could use some sugestion. Thanks!

 

That would be a rich condition.

My suggestion would be, tell us what kind of motor this is; at least, whether its carb or FI, and maybe what year.

 

Oh sory I forgot about thet lol: it's a 1992 5.7L TPI

 

OK then...

Sounds like the coolant temp sensor (in the water outlet, where the upper radiator hose goes) got left disconnected.

 

ok i'll look for that but could it also be some kind of vacum problem?

 

No.

A vacuum leak lets in extra air, not extra fuel.

 

I checked but i did not see the sensor. I asked around and someone told me that they did not have those sensors for a 92. Also a weird thing happened too. I started the car now and it run fine for about 3 min then it started doing it again. My car is an 87 iroc but the engine is a 92 tpi. Don't know if it makes a difference. Thanks!

 

My car had a real bad idle too with the black smoke. But mine would dies at me occasionally when I came to stops. What I did was change the O2 sensor which helped a little so I cleaned out the throttle bottle with some Carberator Cleaner and since then it has been working great. So I suggest you to try clenaing the throttle body first and see if that helps.

 

I checked the coolant sensor by unpluging it, and the car ran perfect. I plug it back in and it starts running like crap so I guess all I need to do is to replace the coolant sensor. Weird problem this sensor created. Thanks for all the help!