1997 Mercedes Benz C230 4Cyl with engine code P0170

Question

CHECK ENGINE LIGHT COMES ON, THEN TURNS OFF AFTER DRIVING ABOUT 30 MILES ON HIGHWAY @ ABOUT 50 MPH. STATE LAW PROHIBITS EXCEEDING THE POSTED SIGNS IN OUR AREA. A SIMILAR CONDITION OCCURS ON A 1999 BUICK LASABER

CLEANED MAF, & AIR BOX FILTER, REPLACED 4 PLUGS WITH,NEW BOSH # F8DC4 GAPED SAME @ 0.032, AS PER SPECS IN MANUAL.

I DRIVE ONLY MOST DAYS UNDER 20 MILES LOCALLY.

WITH THE CHECK ENGINE LIGHT ON I STILL GET ABOUT 23-25 MPG, LOCALLY.
I FEEL IT IS DUE TO A BUILD UP, BEING I DRIVE ONLY SHORT DISTANCES.

Answer 1

P0170 Fuel trim malfucntion Bank 1

When it comes carbon build any built  European cars  can not handle the build up , You can use a fuel injector cleaner to help since you do drive short distance.

Answer 2

P0170 Mercedes-Benz Code - Fuel Trim Malfunction Bank 1
Read more: https://www.autocodes.com/p0170_mercedes-benz.html