2000 Ford F-150 Q&A

2000 Ford F-150 Question: my 2000 f-150 5.4 v8 has a very rough idle

idle is always rough, this problem started as a result of replacing the timing chains. Can this problem be a result of improper timing between the two cams. Could this be the result of a vacum leak.Truck has approx. 220k miles -
Answer 1
why did you have the chains replaced?? did one break?? I would start with a compression test first to check for valve damage. Yes. a vaccuum leak will give you a rough idle. the chains out of time will give a multitude of issues. Roy -
Comment 1
The chains did not break, they were worn and making noise, there was no valve damage. If the EGR is mounted directly behind the throttle body, I removed the vac line that attaches to a diaphragm actuator on this part, put my finger on the connector and felt no suction at all. Removing the vac line did not effect the idle. -