New here and need help! I recently bought a nice 99 f150 with a hydrolocked 4.2 and bought a used engine with low mileage from a 2000 model f150. I had to take the plastic intake off and put the other style on in its place and put one sensor from the old engine on to the new one. Other than that I did not change anything. After installing the engine it fired right up and actually ran pretty good with gas that had been sitting in the truck for about two years. It was totally full so I didnt want to mess with draining it, I added about half a bottle of marvel. After taking it on a long trip around the neighborhood and getting it to operating temperature the cel came on. Went to autozone and they pulled the codes and came up with the following...0102-maf, 0171-fuel trim bank one,0174-fuel trim bank two. I checked the maf sensor with a ohm meter and all the checks pointed to it being good. Checked for vacuum leaks and i think i am good there. I switched oxygen sensors with known good ones. While looking for possible causes of these codes I noticed that the part numbers for the fuel injectors on the autozone website are different and it says that the injectors for a 2000 will not work with a 99 and vice versa. It sure does run good but could this be the root of my problem? I would just go ahead and take the injectors from the old engine and switch them out but I hate to have to buy another gasket for the intake in case the injectors dont make a difference. Thanks for the help.