Horrible idle problem...not the usual surge

[Bigstang1]

about a week ago this problem started with my car. When i start it when it has a cold engine (overnight or when it sits at least an hour) it run really bad. Choppy almost stalling, loading up. Basically sound like a huge cam...cool sounding i guess except my car has the stock cam lol. If i rev it up while its idleing crappy i get black smoke from the tailpipes indicating too much fuel. After i drive for about 5 - 10 mins the problem goes away and i am left with a fairly decent idle with a minor surge that has always been there. Its to the point where i have to keep my foot on the gas to warm it up like a poorly tuned carb. Anyone else had this problem and come up with a remedy? My mods are in the sig if anyone needs to know. I have a check engline light on too btw which, when i pulled the codes b4 the problem started , dealt with the EGR system. thanks

 

[90mustangGT]

So the EGR is working properly?

Assuming that I would get a can of solvent (brake cleaner, carb cleaner) and spray around the intake especailly around the gasket areas and if the idle changes then that is where you have a vaccume leak.

Check for codes again.

The engine coolant temp (ect) going bad will make the motor really run bad as well. It could be many things...

 

[HISSIN50]

and an EGR leaking will degrade the idle to the point of stalling - not unlike what you are seeing, right?

Good luck.