So about 2 yes ago I had a cracked intake manifold and had it replaced..shortly after had low egr flow codes that had me replace every sensor involved on top and three that ford found for me. And fixed...my 01 f150 5.4 super crew has been my best friend last 165k of its 246. So it has a small leak in radiator. Didn't think that would do anything for a bit. Well after almost overheating a few times I pulled up to a job and water was pouring out the top back passenger side....blah blah blah saving 1400 this time I pulled everything to the head.took off intake put back together torqued to 20lbsblah blah...still mix fires at low idle and low rpms.gets worse longer I sit at light have redone plugs switched coil pack at the misfire location..still missing. the round black sensor before the egr out of the intake has good vac in but limited to egr. Don't think this is right...has lean codes both banks....but I also had a PVC not in and the exhaust outflow sensor had a hose knocked off again...misfiring...checking hoses nothing obvious... Perhaps the spare coil is no good now....keep one two handy for wet locations...any sugg here would be greatly appreciated.. Did I not do intake right...and I did use rtv

 

lean codes both banks means you have bad vacuum hoses, not connected, or connected wrong. That will make things idle and run like crap... STart with that, fix the hoses, get all the "lean" codes to disappear, then move on to next porblem if there is one.

 

Lean codes can also mean the intake gaskets are not sealed correctly... but i would fix all the hoses first.

 

I rtv Ed the gasket at say 2am to the intake set it to the head at 10 am was that a big deal...and had hoses of....lean codes will go away or I need to have them reset

 

Runs together , poor definition . What is your current problem ? Lean codes ? Misfire ? Both ?

 

So replaced coil pack plug and boot in no 3 better.. No sputtering but still missing at idle. on no 3 code.... Wondering at this point if its injector also seeing post about IAC valve and this was final solution for last years problem with egr flow.....really tired of buying stuff that's not working can I just soak the injector iseafoam or not