90Mustangfan

Ok heres the deal, my car runs fine when you first drive it, after about 15 min of driving the CEL comes on, then after that when you let the car idle or come to a stop, the idle bounces, it also runs lean after the CEL comes on. then I get these codes....could it be that the MAF grounds out or something, then the CEL comes on, the maf is no longer working proper, thus giving the bouncy idle? could the MAF going out cause it to run lean? what/where would Hego sensor Be? need help fast, I dont want my car to break from running it lean.

11-system pass

Continues Memory:
33-EGR not opening
41-Hego sensor indicateds system running lean (right side)
66-Maf sensor went below .4 volts during last 80 warm up cycles
91 no Hego switching dected always Lean(left side)

KOER:
21-ect out of self test range
41-No hego switching detected running lean (right side)
91-hego sensor cuircuit indicated system lean (left side)
33-EGR not opening

black89gt

i had the same code and problem when i first installed my logn tubes, but the only code taht came up was the EGR not OPEning code, and now it still doenst run right. it ran so much better than before.

Question! does it start like making a popping noise from teh exhaust like a predetonation thing?

HO_85_GT

my dads f150 was getting lean codes and egr flow insufficient codes and running like crap, it was the MAF sensor.

90Mustangfan

anyone...I need help....

lunchbox99

just a guess but I think a code 33 actually means egr NOT MOVING sounds lke egr mighht be stuck open