Do I have an engine timing problem?

[Snowblind-ca]

I have a 2010 Expedition EL with the 5.4L 3v engine with about 180,000 miles. In the last 6 months I’ve noticed the engine starting to make noise (like detonation, engine pinging) when under load and on the edge of a downshift to maintain speed. It does not do this every time, but I can most easily re-create the issue when driving at highway speeds into a hill climb that eventually will require a downshift to maintain speed (often with cruise control on). As the engine starts to work hard to maintain the speed it will start to make this noise and then shortly after downshift. After the downshift, the noise generally goes away.

I took it to the shop worried that I needed a timing job. They said they found the timing control was off and suggested a timing job, which I did (that hurt the pocketbook!). The issue seems a lot less frequent now, but I do still get this noise. I was not able to reproduce it with the mechanic in the vehicle.

The sound is reminiscent of past experience in older vehicles with bad fuel, but it has had this issue over numerous fuel tank refills.

I also recently replaced the thermostat because I was getting some P0128 engine codes. I’ve noticed the engine runs at a higher temp after the thermostat replacement. This was around the time I started noticing the engine noise. Not sure if this could be contributing to the issue.

Thoughts anyone?

 

[JamaicaJoe]

Any misfire codes?

 

[Snowblind-ca]

@JamaicaJoe - Nothing that is triggering a check engine light. Is this something that I can see with a scan tool that wouldn't necessarily trigger a CEL?

 

[Dustin Gebhardt]

Check the exhaust manifolds, specifically the passenger side. Overtime they will crack and sound like a tick-tick-tick under load. I replaced mine with a set of Gibson shorty headers and some remflex gaskets, which fixed the issue. My passenger side manifold had a large crack that was difficult to see without pulling it, but there was some soot visible where the individual cylinder outlet connects to the main part of the manifold outlet.

 

[GaryH]

Could simply be carbon build up on the valves or cylinders. Try adding some Techron for a couple of tanks and switch to a top tier gasoline.

 

[iowacarpenter]

Yeah pre-ignition is often due to low octane gas. Try switching to a higher octane or adding an octane booster. The fact that it append when lugging is indicative of pre-ignition to me.