Help! blackens the exhaust pipes after only a few miles

[GARY 53]

Car runs fine getting around 19 mpg around town but blackens the exhaust pipes after only a few miles.No smoke, no CEL why the black pipes so quickly?
98 octane fuel

 

[dougelam]

Most might remember back in the day you knew your engine was running good by looking at the tailpipe.
If it was gray it was running at its optimum.
GM cars with fuel injection have always run on the rich side which in turn leaves a black residue on the tailpipe.

Try starting it up and driving that same distance like a little old lady meaning a very gradual accell up too speed and see if you get the same results.
Let us know

Sent from my SM-N920P using Tapatalk

 

[GARY 53]

I have tired that i will still blacken the pipes after a few miles
it is like it is running with the coke on in a engine with a carb