asennett

Hello everyone - I hope you can give me some guidance.

I have a 2005 F150 5.4 with 200,000 miles on it. I purchased the truck over a year ago with 175,000. The truck had the common phaser tick so 2 months ago I put a new timing set (chains, guides, tensioners, phasers) on the truck. No sludge and everything looked good for a truck with this many miles. I saw evidence that the passenger side chain was hitting the timing cover (that explains the rattle on start up). No broken guides. After replacing the timing set, the truck started fine and runs good - for about 3 weeks.

I started getting a slight rattle at start up and after the truck has sat over night. The problem is getting worse and now I get a code P0340 and the truck will die after it is warm and I come to a stop (idle). The rattle happens at every start up now and is louder. If I tap the gas - it seems to correct the problem of the rough idle and dying.

Note: Since I have owned the truck I always use Mobile 1 5w-20 syn oil and Motorcraft filter.

I have inspected and swapped the VCT Solenoids to see if anything changed and nothing changed (still get P0340 and same problem).

What else can I check before I have to open the front end again?
Is it common for new tensioners to fail?
How can I tell if this is a tensioner problem or an oil problem?

Any help would be greatly appreciated!

joshtowal

If it's a 2 wire cam sensor, measure the resistance of the sensor. Should be between 300-425 Ohms.

asennett

Sensor checks out ok.
How do I know if the timing code and stall at idle is related to the timing or as a result of the low rpms at idle?