2004 Ford F-150 Repair Question
Topics covered: Compression, Crankshaft, Sensor.
Mileage: 86,000 miles.
Mileage: 86,000 miles.
Asked on February 8, 2012
04 F-150 5.4L 4x4 rough idle
Truck has rough idle for about three weeks. Not bad at first but now its bad. Check engine light came on about two weeks into it. Code said misfire on #7 & crankshaft reads rough run in first thousand RPMs. So I changed the 7 coil. Still rough & light came on again so I changed plugs, fuelfilter, still the same. Checked for vacuum leak with carb cleaner on the intake manifold. No change but cant get under manifold, so i changed the intake gaskets anyway. No change. I took it to Ford dealer today they said no vacuum leak they think its a bad valve spring or valve on #7. I read on one of the other posts that it could be a crankshaft position sensor (CKP). I need some help please.
Asked by pvsfx4Answer
Replied on February 8, 2012
Have you checked compression?
Here's the test procedure for the CKP sensor. Download the file and change the extension to pdf.
Replied on February 8, 2012
Yes, the service guy told me compression checked ok. I questioned him if the compression was ok on #7 why would they think the valve was broken or bent. It just sounded kind of odd. It seems that there are alot of people with the same problem at just about the same mileage. If you look on a few different sites.
Replied on February 8, 2012
It sounds funky to me too. Try the diagnostic I gave you. You can borrow a compression tester from most parts stores like O'Reilly's, Pep Boys, and Autozone.