Hello!

I have 2004 f150 small v8 (4.7?)

Has about 92000 miles.

When warm truck runs excellently.

At fiurst start up the idle is very rough and raw gas smell for about 4 minutes then truck runs like new. Will start and restart great until it cools down overnite.

My actron says missfire cyl 3.

Dealer did a lot of stuff ($1700).
Did not fix it. Dealer says that on start up compression is zero in cylinder three but is 100% when it warms up.
Suggested I run seafoam through it.

He thinks it has a vacuum leak or carbon at start.

In my limited knowledge I am thinking:
sticky lifter
bent push rods
warp valve

Any ideas on this appreciated.

 

It has to have a valve sticking open if number 3 is dead then goes back to making compression.
You could try changing the valve springs and lifters on the intakes and exhaust valve on cylinder 3. New spring tension may help alleviate the issue.
New lifters of course as the old ones also may have issues
4.6 liter BTW

 

Thanks for reply.

Yeah. The dealer replaced coil, plug, and injector after I had already done the same things.
Dealer said the truck wasn't worth fixing. But a new truck is $40 k or more.
Mine has good paint, body , shell and pulls my liteweight trailer just fine.

So looking for info so I can check at some non dealer repair shops.

I was being optimistic on the 4.7 lol.

 

Keep in mind , the spring lifter replacement may or may not work .
But you certainly need to look at the valve train and see if something is going on, so the cover needs to come off for inspection.
It could be the a valve has gauled in the guide, due to overheating or poor oiling.The head may need to come off.If it is an oiling problem that too will need to be addressed.
Putting a few new pieces may get you buy for quite a while and cold clear up the problem.It is worth a try.

 

OK Thanks Leroy.

Gives me some encouragement. I am retired teacher and hope to travel some for the next few years and hope to get by without a new truck.