Allinkdupp

Here is what mine was..... Wrong plugs, doesn't seem right but I took out the autolite and put in motorcraft and bam... All better, these trucks really don't like other plugs

Tommy J

Ahh, The dreaded idle of these trucks. I've replaced more stuff than everyone combined and still have the low/rough idle after mostly motorcraft replacement parts. You can try the so called relearn but just driving it around does the same thing. I don't know why so many of us have these problems after trying to better our ride. I also have a cat converter issue and was told that it does'nt cause an idle issue but............... other guys have said it might. You hate to throw in some new cats and fry them with a mysterious possible unsolved misfire or something. I don't think any 2 idle issues are the same but we all share the same frustrations. No one ever suspects the fuel pumps. Good luck

Tommy J

Theres also a fuel pressure module under the spare tire that gets rusty and rotted, check that out too

tcp2

Battery relearn
Because your vehicle’s engine is electronically controlled by a computer,
some control conditions are maintained by power from the battery. When
the battery is disconnected or a new battery is installed, the engine must
relearn its idle and fuel trim strategy for optimum driveability and
performance. Flexible fuel vehicles (FFV) must also relearn the ethanol
content of the fuel for optimum driveability and performance. To begin
this process:
1. With the vehicle at a complete stop, set the parking brake.
2. Put the gearshift in P (Park), turn off all accessories and start the
engine.
3. Run the engine until it reaches normal operating temperature.
4. Allow the engine to idle for at least one minute.
5. Turn the A/C on and allow the engine to idle for at least one minute.
6. Release the parking brake. With your foot on the brake pedal and with
the A/C on, put the vehicle in D (Drive) and allow the engine to idle for
at least one minute.
7. Drive the vehicle to complete the relearning process.
• The vehicle may need to be driven 10 miles (16 km) or more to
relearn the idle and fuel trim strategy along with the ethanol content
for flexible fuel vehicles.
• If you do not allow the engine to relearn its idle trim, the idle quality
of your vehicle may be adversely affected until the idle trim is
eventually relearned.
• For flexible fuel vehicles, if you are operating on E85, you may
experience poor starts or an inability to start the engine and
driveability problems until the fuel trim and ethanol content have been
relearned.

chevykiller666

I just had my plugs, boots/ springs and 1 coil changed this past Saturday. The shop installed Autolite plugs. I told him about the truck " liking " the MC ones, he said that's because the dealer want you to buy from them. 5 days later and my truck still runs smooth and starts better. I also had 222,xxx Kms with original plugs, lol.

tstone3

You do realize the original plugs you speak of would have been Motorcraft? I have heard nothing but bad things from people that have replaced with anything but the Motorcraft plugs... I hope this isn't the case for you and the Autolites work out for you. You will want to recheck your plugs after a couple months, I just had to check all mine as I had one loosen up and the truck started rough idling and fuel mileage had plummeted. I had done them approx. 6 months prior.

Tommy J

Just curious, did your rough idle/loose plug throw a code? I did mine a few months back and had a fuel smell a month later and found one had loosened up. but i have been chasing my rough idle for months and replacing stuff left and right. I know I have a cat issue but am wondering if I should check the plugs again. Just how loose was that one plug? I was kind of concerned that one of mine was loose so I checked them all, even moved the pcm again. It was 2 months ago so now you got me curious and wondering............. what if??????????????????

LEN671

In for this solution as well. Mine is still acting up even after doing the "Re-Learn" process.

tstone3

No, actually it didn't throw a check engine light. The plug had backed quite a ways too and I'm thankful I caught it or it could've pull some threads out if it became much looser. The truck also had developed a pretty noticeable tick, almost like a manifold leak but was hard to distinguish where it was coming from. I would check your plugs again to be on the safe side. Let me know what you come up with. Does your truck have any tick noise coming from the engine?

LEN671

Mine does in regards to the ticking noise.