First off hello and thank you all beforehand. This is my first forum post and it’s about my first F150 truck. This started as a head job but since everything was taken apart I figured let’s rebuild the whole thing. I’ve just finished rebuilding my motor after 2 months ( cutting **** out that was welded and rewelding) and started it up today. It drives good just idles roughly and I’m getting no codes even after driving it for an approximate 10 mile test drive. The warmer the engine gets the tougher it idles. I’ve tested for vacuum leaks on the intake, elbow, and throttle body. Those are good. Spark plugs and ignition coils are new. I personally have come up with a few things that may be affecting the idle but wanted the input of the F150 community. Here’s what I’m thinking....
- it’s a rebuild and needs it’s time to break in
- time to replace the O2 sensors and possibly the cat
- clean or replace MAF sensor
​​​​​​- there’s a vacuum leak I missed
- dirty or faulty fuel injectors

thats what ive hot but I want input from everyone else as well and once again thank you. I’ll add links of videos with the idle before and after rebuild when I get them uploaded.

I’ve got two injectors with connections loose at the bottom connecting to the intake. They wiggle a lot. Think they’re leaking out at the bottom? If so would I need new injectors or replace the bottom o-rings?