‘03 F-150 FX4 5.4L auto
Hi all so here’s what I know is wrong with my truck: it needs spark plugs and/ or coils because the idle in Park is shaky and unsteady. Another problem that I noticed just recently: it has a rotten egg smell coming from the exhaust, mostly noticeable when the truck’s on and it’s stopped. I was wondering, since the truck has what seems to be a misfire, will changing ⚡️ plugs and ignition coils fix the rotten egg smell? I was just wondering and hoping this will fix the both the problems the truck has. Either way I eventually need to change everything (cats and ignition stuff) but yeah I was wondering what approach I should take etc. also was wondering if bad ignition stuff is even associated with egg smell at all? Thanks for the help!!

 

That smell is from excess hydrocarbons in the exhaust. Fixing the engine performance will help. If plugs and coils are needed anyway go ahead and get it done then see if the smell problem still persists.

If the smell is still present then further diagnostics can be performed.

 

Plugs and coils will help the tune up needed, but there another spot you need to start looking into. Vacuum hoses and leaks,,on fuel injected engines vac leaks can cost power and fuel economy . Very easy for a vac leak to help cause some of the problems your talking about, Small ones can happen and not even throw a code. Are there check engine lights on ?

 

Thanks for the reply, no there are no codes, and I just fixed 2 major vacuum leaks not too long ago that were associated with the 4WD system, and from what I can see there are no vacuum leaks anymore. Worst case if the plugs and coils don’t help I’ll have a mechanic use one of those smoke machines to find a vacuum leak (diagnose the vehicle)

 

Use Motorcraft plugs and Motorcraft, Denso, or Delphi coils. Torque the plugs to 28 ft/lb and use a small amount of dielectric grease in the coil boots.

 

Thanks for the suggestions, I ended up ordering Motorcraft Spark Plugs and Denso Coils. I’ve heard that Denso makes Motorcraft stuff, and it’s somewhat cheaper than Motorcraft! Might as well order the Densos lol.

 

hopefully you didn’t ruin the catalytic converters

 

How so?

 

Misfires can clog them due to all the unburned fuel. That's what causes the smell.

 

I don’t think I directly contributed to the cats being ruined though. The previous owners who had it before me were retards who put 4 Autolite spark plugs and 1 new ignition coil and 4 other plugs were Motorcraft. I’ve only had the truck 5 months, and I also had to get a little Ryobi Vacuum to vacuum out dirt, rust, and even tree seeds from inside the spark plug holes.

 

Changed spark plugs, old and new



Before photo: so much f**king grime that the socket wouldn’t grab the spark plug




After: I had to clean and scrape it up then vacuum it out with a little Ryobi vacuum that my dad made a custom nozzle so it can fit in the hole.

 

The smell can also come from sulfur in the fuel you put in the tank. I refueled at a Standard Oil Station once that had a load of high sulfur fuel. It was quite objectionable.

- Jack

 

Just had another thought,,how about mass air flow meter. They can go bad and not show a code and allow extra fuel being sent through the injectors causing unburnt fuel to leave the exhaust , with rotten egg smell resulting.
Might need to read your fuel trims. Most code readers now have the capacity to do so.

 

Hey! I think I MAY know who you are. Do you own my old ‘97 F250 light duty? I remember the name since I always take pictures of title release papers since I’ve been accused of tickets and fined in the passed for stuff the new owner of my sold vehicles have done.

If so, how’s the truck? 😁 I took good care of it (only had it for 6 months) and lost a lot of money on that ol thing.

 

Naw , thats not me, I have a 99 model 4 wheel drive extended cab with 90 k miles on her. She's in good shape though and gets me along the old timber roads in the back country Mts of south western parts of Virginia.