Car Forum World

Car runs good when its cold but when it heats up it starts popping a little and light black smoke starts coming out of the exhaust. It also has a rough idle to it and has a bad odor. it is not the catalytic converter or the oxygen sensor because I have replaced both. It does not seem like it is lost any power either. The check engine light is on and when I check the code it just says that the system is lean. Does anybody have any ideas? it is not a big issue but I could like to get it fixed.

You have a vacuum leak someplace. Look around under the hood and see in loose or broken vacuum lines. A stuck open EGR valve will do the same thing, so check to see that it's closed totally. You may have to remove it and examine it to see if a part of carbon has it held open. The MAP sensor is reacting to the low vacuum, but it is not the problem or there could be a MAP sensor code.

I think I could start by checking the intake gasket to be sure it's sealing properly. The next thing I could check is the EGR. be sure it's sealed good and the vacuum lines are good leading to and from it. I could check your MAP sensor next. They can influence some number of things that will trip the check engine light. I could check your fuel pressure when it's cold and when it's hot. You may have a flawed pressure regulator . I could reset the codes after you check things out and drive your car on the highway for 15 or 20 miles. If it's still puffing black smoke then run some fuel injection cleaner through it. You may have a dirty nozzle or a sticky injector or something like that. Good luck.