FORD 5.4 V8 HELP!!!!!

Anonymous-0 · Dec 19, 2011

I have a 5.4 gas in my 2003 F250. I have replaced parts till my head is spinning. I have No check engine lights on at all. When the truck starts up cold it runs fine, when it warms up a bit it "misses" under load, even in park when its warm the RPMS will fluctuate and its intermittent. It will idle at 1000 rpms, but the tach will move above and below the 1000 mark the width of the idicator - not much. Ive replaces fuel filter, injectors, and now the puel pump. Im running out of ideas....and with no check engine light I cant use engine analizer....help please.

Allan in NE · Dec 19, 2011

Plugs and/or coil packs.

Allan

Sean Feeney · Dec 19, 2011

E- bay # 280709437167

Ken Macfarlane · Dec 19, 2011

Coil on plugs and boots. They all say it will trip the light but mine didn't with 2 bad ones. Same symptoms.

Ken Macfarlane · Dec 19, 2011

BTW I got motorcraft ones off Crown Vic 4.6's at the scrap yard, I've heard the chinese cheapies on ebay have a very high failure rate. I paid 100$ for 10 of them.

Anonymous-0 · Dec 19, 2011

plugs are good for 100k miles, after that not so much. If you're close to that change them. HTH, Pete

Bowlegs · Dec 19, 2011

check the vacuum lines on the back of the engine. They are a pain to replace but have had 3 trucks with the same problems. Vacuum leak on all three.

dhermesc · Dec 19, 2011

This guy has an idea:

http://troubleshootmyvehicle.com/ford_misfire_4.6L_5.4L/misfire_code_testing_1.php

Greg_Ky · Dec 19, 2011

If you change the plugs do it just as it says in the TSB and be prepared for broken plugs. (top half with threads breaks off and leaves the bottom half stuck in the head). I changed mine at 50,000 and only broke one.

atlarge54 · Dec 19, 2011

Mine had obvious static in the radio when tuned to an AM radio channel it varied with engine speed. On two different occasions an obvious miss which was worse under load. Had bad COP. No check engine light either time.

Changing plugs kinda sucks but it is do able. It helps having a small metric gearench. Loosen and raise the fuel rail on the drivers side. I was also told to use Motorcaft plugs, something about the threads have different treatment for aluminum heads. Is it true, I don't know?

dhermesc · Dec 19, 2011

You only want to use Motorcraft or Autolight copper plugs - for some reason the platnum plugs cause issues.

The torque spec is VERY IMPORTANT on that year of 5.4 engine. Its an aluminum head with only 4 threads on the splug, its extremely easy to strip the threads by over torque (only 12 to 14 ft. pounds torque).

Its also not uncommon to strip the threads out of the head when you loosen them - the aluminum galls to the spark plug and just rips the out. So make sure you can get the wrench on square.

BillyinStoughton · Dec 19, 2011

The gentleman below is pointing you in the right directin regarding a possible vacuum leak. I have a 01 F-150 with a 5.4 with 236K on it and it was doing the exact same thing! In my case it was an intake manifold gasket. Let"s hope in your case its just a hose. Its not that uncommon especially with a truck of that age. Good luck!

Bryan inIowa · Dec 19, 2011

Need more data !!! Fuel trims ? Take it in and have a GOOD shop scan it . Lot of drivability concerns will not set a code . I have replace many intake gaskets on these .

robgIN · Dec 19, 2011

thats only on the 2004 thru 2007 5.4 3 valve. He says he has 2003 so still 2 valve engine, totally different spark plugs, apples and oranges.

robgIN · Dec 19, 2011

sheck your pcv hose really good. Sounds more like a coil on plug issue. People waste a lot of money trying to save themselves money and fix it themselves by throwing parts at it without diagnosis. Call around to dealer or decent shops, most places around here will give you a decent diag for an hour or less charge, May sound like a lot at first but usually ends up being way cheaper in the long run. Shouldn't be that hard to diag with the right equipment .

David G · Dec 19, 2011

Mine had a bad coil, did not throw a code. I would take it in before throwing parts.

ben brown · Dec 19, 2011

number 5 plug coil was what was wrong with mine and have two friends same thing

Bryan inIowa · Dec 19, 2011

They are a joy to work on "eye roll " . I do have kits to install inserts for all these motors now ..Even ones that strip or blow out the thinner inserts .

meanmtn · Dec 19, 2011

i had the exact same problem with my 99 f-250 v-10 no codes turned out to be the egr valve. i learned the hard way, i brought it to ford and payed dearly.

Hobo,NC · Dec 19, 2011

I have been lucky,,, never broke a plug are had one to blow out... I have done 20 are so but did do my home work first.... If I can not have the truck for 3 days I don't take on the job... Once I have done my prep (takes 2 days) I take the plugs out with a air ratchet :shock:

Motorcraft OEM plugs all the way....

FORD 5.4 V8 HELP!!!!!

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