My engine has had a knock ever since i got it, and ive been hearing a loud buzzing sound coming from the maf sensor so about three weeks ago i replaced the maf with a used one, ran the same for about a day. then it started to bog down really bad, and the truck would shake really bad on the highway, it just lost all of its power, so i put the old maf back in. the problem still didnt go away, so after talking to numerous mechanics i was under the assumption that my engine had died ( lost a cylinder).
I already had a used engine ready to go in so i decided to replace the engine. after replacing the engine everything seemed fine until i went down the road and realized that it has a very similar problem as far as the no power issue goes almost like its stuttering, so i ran the codes and got p0304 (misfire cylinder 4) and p1132 which i believe is a running rich problem. the exhaust definitely smells like its running rich. could this be an o2 sensor problem that still exists, its def not the new eng (i had it running before it was removed from the old truck and it ran great) im assuming that it has to be something to do with the comp or maybe along those lines. any help or suggestions would be greatly appreciated