5.0 making concerning noises

[GT2000]

So in the last few weeks I've noticed my 98 explorer has been harder to start, only when it is fully cold, no real problems when warm. The other day i drove it around doing errands all day, no issues other then a hard cold start, and then later to work. When i went out to start it after work, 30-40 degree's, the motor has a slight tick or tap and miss to it. Shut it off, checked the oil, it was fine, started it back up and sounded fine, not missing anymore, so i drove it home no issues. Next morning, cranks hard and tap tap tap, much louder now, along with a miss. Didn't run it long. My reader says cylinder 5 misfire. This morning i go start it up just to confirm what cylinder. About a minute of it running the miss went away, and then a few seconds later the tap goes away completely. Not even a tick or anything. Now its quiet and running smooth as a baby. Let it run 5 minutes, ran like nothing was ever wrong. Anyone have an idea what could be going on?

 

[Turdle]

stop right where you are, pull the #5 spark plug and show us a picture. Thinking your #5 injector is leaking down, washing the cylinder of oil

 

[CDW6212R]

Subscribing.

My new 98 has a similar ticking at cold start, oil pressure shows fine. An injector is a good idea, I'll add a fuel additive to mine again. I did it when I first got it a month ago, the ticking is just recent with the colder mornings. I'd like to replace the O2 sensors also, just not high enough on my list yet.

 

[koda2000]

For the ticking noise, I'm thinking maybe a lifter that's sticking. Try putting in a quart of Marvel Mystery Oil (or even ATF) just before doing your next oil change. Run it for 100 miles before changing your oil and see if that helps.

It's strange that the miss is happening only when you're hearing the ticking noise and that both go away at the same time. Checking the #5 spark plug might tell you something.

 

[GT2000]

Here is a pic of the number 5 spark plug, and compression test on the cylinder. Engine was cold at the time. Spark plug has only been in there 3-4.000 miles.

 

[Turdle]

That looks good, maybe kinda whitish but not black and sooty like I was expecting to see. . the compression looks great.

Could be an injector not firing or even a stuck lifter noise. what weight oil are you using? filter brand?

Marvel mystery oil is good stuff. you might try adding a quart, drive a while, then change oil to 5w20 , motorcraft filter and a bit more MMO , and, add some real good injector cleaner for the next 2 tanks of fuel.

Does your oil " gauge" jump right up when the engine starts?

 

[974X4BLACKSPORT]

Dont forget to check your spark plug wire/wires. Arcing splug wires can make a tick or tap type noise too.

 

[GT2000]

I run conventional 5w30, purlator filter i think. The noise is Definatly noticeable from the top of the engine. If it is a stuck lifter, what would help loosen it up?? I know they sell “motor flush” of some sorts, dont have and experience with that stuff. U think mystery oil may help it? Seafoam?

 

[koda2000]

Maybe it's just the pic of the spark plug, but that gap looks huge. S/B .054. The business end of the plug looks okay to me. Maybe a bit white on the insulator, which would indicate running lean. Usually the insulator should be more of a tan color. Compression looks okay. Why are the plug threads so rusty looking?

 

[GT2000]

Bottom of block surface is rusty, long with the rest of the truck lol, threads kinda are too but the spark plug screws in fine so, idk? Maybe i need to check the gap on it, like i said, plugs and wires are fairly new. Any sorta reason it would run lean? I have an unpluged egr right now so P0401 and a P0420 had for awhile. The cylinder 5 miss code is the only new code.

 

[donalds]

That plug looks good
Regap as koda says

 

[koda2000]

If only that one cylinder (#5) is lean then your lean condition can only be fuel related. If they're all running lean there are a lot of things that can make your engine run lean (eg: vacuum leaks, dirty MAF, low fuel pressure, clogged fuel filter).

 

[GT2000]

Just the one cylinder, and with that bad noise it makes, wonder if it could be a lifter, or something messed up with the valves, cause when it quits tapping loud after about a minute, it doesn't even have a light tick or anything anymore. And on warm start up doesnt have any problems.

 

[Mbrooks420]

Are those factory Motorcraft plugs? The 5.0 is picky about plugs. Plug looks lean to me. I’d pull another out of that head and compare.

First bet is a stuck lifter.

 

[GT2000]

Autolite platinum or dbl platinum, on of those, had in for about a year, no issues, dont think its the plugs. Plug and wires that were in prior to that were likely original. Im guessing something is up with the lifter, gummed up maybe.

 

[koda2000]

I usually use Autolite double platinum spark plugs in all my Fords. Never had any problem. Motorcraft brand spark plugs are made by Autolite so they're really the same.

 

[GT2000]

I usually use Autolite double platinum spark plugs in all my Fords. Never had any problem. Motorcraft brand spark plugs are made by Autolite so they're really the same.

I dont know the maintenance history on this truck, but i have hunch that it wasn't the greatest cause i needed all the ball joints done when i bought it, trans fluid looked nasty and possibly original at 140k, oil looked so so, i changed right after i bought it, now it has 145k. Plugs and wires Were likely original as well, when i bought it. Also, dont forget the fact that he had a "lamp cord" or something running over the window washer motor from the battery for some reason??? Also the hood release and struts were shot, he used a pair of pliers to pull the steel cable to open the hood, and a metal stick to hold the hood lol. This poor thing was unloved, interior and body are actually nice though, sept for some underneath rust. Only paided $500, and literally cleaned out 40$ worth of change out it haha. Also came with some brand new rear brake pads.

 

[koda2000]

I dont know the maintenance history on this truck, but i have hunch that it wasn't the greatest cause i needed all the ball joints done when i bought it, trans fluid looked nasty and possibly original at 140k, oil looked so so, i changed right after i bought it, now it has 145k. Plugs and wires Were likely original as well, when i bought it. Also, dont forget the fact that he had a "lamp cord" or something running over the window washer motor from the battery for some reason??? Also the hood release and struts were shot, he used a pair of pliers to pull the steel cable to open the hood, and a metal stick to hold the hood lol. This poor thing was unloved, interior and body are actually nice though, sept for some underneath rust. Only paided $500, and literally cleaned out 40$ worth of change out it haha. Also came with some brand new rear brake pads.

Well if the problem is a lifter that's sticking, as I suggested earlier, you can try putting in a qt of Marvel Mystery Oil or a qt of ATF into the engine just before doing an oil change (50-100 miles before). Both are high-detergent fluids. If a lifter is sticking because of dirt or varnish doing this may free it. Of course, if the lifter has mechanical damage it wont help, but it's worth a try IMO as the noise is intermittent, but I've never had a sticking lifter that was so bad it caused a miss.

Believe me I know about buying a cheap unloved vehicle. I bought a 2001 Sport Trac about 5 year ago and have a list of repairs that's now well over a page long. Right now the engine is out and I'm rebuilding it and the transmission. Biggest vehicle purchase I've ever made in my life (and I once bought a 4 cyl Jeep Wrangler, which was my second biggest vehicle mistake).

 

[410Fortune]

if the computer is giving you a misfire on cyl #5 code then your issue is likely an injector
The engine computer has a hard time determining the exact cylinder of a misfire in the ignition
It can detect a misfire in the fuel system right away
9 times out of 10 if the 5.0 computer gives you a misfire code, especially if it pops right back up, then its almost always an injector issue
it would take several drive cycles for the computer to determine what cylinder is misfiring through the ignition.

With the amount of neglect this drivetrain has seen its not a bad idea to remove the upper intake and check out the fuel rail and re seal everything up with new gaskets and O rings
Skip the Purolator oil filter they are not very good, use Motorcraft they are cheap enough, your engine uses a 820s

FYI you can get 8 re manufactured and flow matched injectors for well under $100 shipped
I would also replace the plugs and wires, DO NOT use cheap plug wires.
Autolite or Motorcraft double platinum plugs gapped to 0.054"

Other sources of a ticking noise would be blown out exhaust gaskets or cracked exhaust manifolds, pretty common on these trucks
Also a cracked EGR metal line on the passenger side will make a nice ticking noise
Many exhaust leak ticks may only be present at first cold start, as things warm up the metal expands and leaks are closed = ticks go away

A misfiring injector/cylinder can also make a nice low ticking noise

Good idea to change your fuel filter when you do new injectors as well
You can also remove and bench test your current injectors if you are cheap like me, I have seen many plugged stock injectors come right back to life with a good bench cleaning/test

 

[koda2000]

if the computer is giving you a misfire on cyl #5 code then your issue is likely an injector
The engine computer has a hard time determining the exact cylinder of a misfire in the ignition
It can detect a misfire in the fuel system right away
9 times out of 10 if the 5.0 computer gives you a misfire code, especially if it pops right back up, then its almost always an injector issue
it would take several drive cycles for the computer to determine what cylinder is misfiring through the ignition.

With the amount of neglect this drivetrain has seen its not a bad idea to remove the upper intake and check out the fuel rail and re seal everything up with new gaskets and O rings
Skip the Purolator oil filter they are not very good, use Motorcraft they are cheap enough, your engine uses a 820s

FYI you can get 8 re manufactured and flow matched injectors for well under $100 shipped
I would also replace the plugs and wires, DO NOT use cheap plug wires.
Autolite or Motorcraft double platinum plugs gapped to 0.054"

Other sources of a ticking noise would be blown out exhaust gaskets or cracked exhaust manifolds, pretty common on these trucks
Also a cracked EGR metal line on the passenger side will make a nice ticking noise
Many exhaust leak ticks may only be present at first cold start, as things warm up the metal expands and leaks are closed = ticks go away

A misfiring injector/cylinder can also make a nice low ticking noise

Good idea to change your fuel filter when you do new injectors as well
You can also remove and bench test your current injectors if you are cheap like me, I have seen many plugged stock injectors come right back to life with a good bench cleaning/test

OP - I agree that cyl #5 may likely have an injector related issue. Along with the injector itself and the O-ring seals, on the 4.0L SOHC engines the injectors sit in a plastic piece, called a "fuel injector adapter". (IDK if the 5.0L V8's have these). These plastic sleeves get brittle over time and crack/crumble. Below is a pic of the 4.0L SOHC fuel injector adapters. When they break down they can cause an air leak, which will make a cylinder run lean. Your very white #5 spark plug indicates that at least cyl 5 is running lean, It might be the injector, the O-ring seals (or the adapter if the V8 uses the adapters). Have you checked any other spark plugs for color?