Q: Shaking noise when the truck idles, worse when it first starts

(Answer assuming it is a 5.4 Triton Engine)

This complaint is one of the most common I have heard over and over again for the Ford F-series trucks with the 5.4 Triton engine and covers many other years besides just the 2008. The 5.4 Triton engines have major issues with the cam phasers and timing chain tensioners causing rattling, knocking noises along with several drive complaints. In your case you ask: ‘How can I fix this for good?’ Well after thinking about that question for a while, my answer would have to be nothing can be fixed for good, but only fixed right the first time. To fix your problem you will have to first diagnose it properly. Contact YourMechanic for a qualified mechanic to listen to the noise and verify the problem is with the cam phasers and not the previous repair done incorrectly. If the previous repair was done correctly, then continue to replace your cam phasers. If timing of the cams were not set correctly, then you will have to have it set up correctly with new cam phasers installed as well. Once this is done change your engine oil and filter with 5w20 oil and clear any check engine codes. Start engine and noise should be gone. A side not to consider: if your tensioners came apart and particles got into your oil pan then, the oil pump intake screen may have got clogged with this debris from the tensioners and caused a loss of oil pressure. Check with the mechanic who did this job and see if this was the case. The bottom line you should have the cam phasers replaced first, then adjust the timing chain and tensioners as needed.