First off Im a diesel tech cars are not my specialty... I had a type A misfire (flashing CEL). Pulled the codes and found p0303, p0171, p0174. Fuel trim was in the 38%, found broken pcv elbow. Replaced it cleared codes, but now I have a stumbling off idle to roughly 2K rpm, and lack of power under load. Fuel trims are down to roughly 8% at ST Lt is roughly 10%. Tested EGR valve by applying external vacuum and it will stall the truck with vacuum applied. No codes are present at this time, no pending codes either. Truck has new pcv valve, elbow, and fuel pump, cleaned the MAF, Top end and injectors. Will the KAM cause this issue? do I need to do the relearn procedure?
Had rough idle and Type A misfire. codes p0303, p0171, p0174. on 1997 Ford Expedition
by Joe Book in Humble, TX on June 03, 2012
2 answers 1 comment
ANSWER by globalhelper on June 03, 2012
look at pcv hose from under throttle body very common to have vac leaks at that hose,can cause all three codes
COMMENT by Joe Book on June 03, 2012
I already replaced that as stated in the post.
ANSWER by PARTS GUY on June 03, 2012
You have a bad ignition coil on number 3 cylinder