5.4 highway patrol f150
 

Hey everybody. I just bought a 2010 f150 at an action in Phx AZ, Its a former highway patrol truck. I bought the truck as is. All the description said was, Its runs and drives, and was in fair conditions. The interior of the truck looked hardly used at 150,000 miles. $5000. So I bought it. I noticed it had what I thought, seemed to be a u joint, jerking, and ticking problem in the engine. Drove it from Phx to Tucson. and it started rough stumbling and knocking sound, after the 90 mile trip. Engine light came on with a PO306 code(misfire #6). went to start it the next morning and the knocking noise was more severe( like hitting a plastic can with a stick sound). Sound seems to be from the upper part of the engine.
I was wondering if anyone can point me in the right direction as to where to start looking. I have absolutely no knowledge with the 5.4 3v engine. I pulled the plug from #6 and it was charred up pretty good.
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If it's only one cylinder, then first suspect would either be leaking injector or faulty coil. The easiest is replacing the coil and trying that.

Though, at 150k, I would replace all of the plugs and coils. Use only Motorcraft.

In fact, since it was probably classified as "heavy service", I would recommend doing a full tune up on it. Including flushing the coolant.

If you search, you'll find a bunch of good information about the 5.4l 3v.

As for parts, I recommend Rockauto or Tasca.

Good luck.

Phaser knock. You are probably in for a new timing set and high volume oil pump.

As stated, a possible phaser knock but that usually sounds more like a diesel engine knock. I'd also be looking for a cam follower gone bad. Pulling a valve cover can pretty much tell you about that. Might try to localize the sound using the stick method. Get a stick of about 3 feet in length and place it on different parts of the engine. Put your hand over the other end and put your ear on your hand. It's a poorboy stethoscope. I'd start at cylinder #6. If the exhaust cam follower is bad, the engine will keep cramming fuel into a cylinder that that exhaust side isn't working right and will foul the the plug.

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Well, I pulled the valve covers off. I found the exhaust roller follower had been spit out on #6 cylinder. Cam lob is scratched up and lifter has some knicks on it.

An unrelated question. What kind of tires are on it?

https://cimg1.ibsrv.net/gimg/www.f15...b99123fc56.jpg
255/65/R17 Bridgestone Dueler AT

I ordered new lifters and rollers. Was thinking about reusing the camshaft. It's marred up, but no deep scratches or chunks missing. Anybody have any thoughts? To reuse or replace cam?

Keep in mind that there are no removable/replaceable cam bearings.