Need help on engine swap

[mont]

OK I have two expedition the 98 has bad motor the 99 has a good motor and crash body. I pulled the 99 motor an transmission reinstall it in 98 shell .Started it up after the install the engine sound and run ruff misfire and no check engine ligth.Is there any more part has to be swap to make this truck run right?

 

[khpony]

My first thought is did you change the computer also?

 

[99 Expy]

I read your other post, and I think that it could be the different computer. I am not sure what differences there are on the 5.4 PI and non PI heads, but I know on the 4.6 engines, the combustion chamber and pistons are different, yielding a different compression ratio between the two. If that is the case, your computer may not be accommodating that and making it run rough. Just an idea.

 

[flyin]

try to identify which cylinder or cylinders are misfiring by unplugging the coils and listening for rpm drop then pull the valve covers and check for cam followers that fell out due to lack of oil pressure on startup. It happened to me while doing an engine swap